EFFECT OF NON STARCH POLYSACCHARIDES OF CEREAL GRAINS ON DIGESTIBILITY AND INTESTINAL MICROFLORA OF CHICKENS AND GEESE

Andrzej Wiliczkiewicz¹, Janusz Orda², Dorota Jamroz³, Jolanta Skorupińska^1
1 Department of Animal Nutrition and Feed Quality, Wrocław University of Environmental and Life Sciences, Poland
² Department of Animal Nutrition and Feed Management, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Science, Poland
³ Department of Animal Nutrition and Feed Management, Wrocław University of Environmental and Life Sciences, Wrocław, Poland

ABSTRACT

The examination was conducted on adult cocks and ganders. They were fed with concentrates of a diversified level of structural carbohydrates fractions. It was obtained by applying different cereal grain types as a diet base: maize, wheat, barley, oat and rye. The diets based on oat and barley included more dietary fibre and cellulose complex components. The authors compared the influence of various cereal grain types (maize, wheat, barley, oat and rye) on the content of dry matter and structural carbohydrates fraction (crude fibre, NDF [Neutral Detergent Fibre], ADF [Acid Detergent Fibre] and hemicelluloses) in ileum and colon content as well as their digestibility in chickens and geese. Besides, the influence of the mentioned grains on the concentration of short-chain fatty acids (SCFA) and pH value of these birds’ intestinal content as well as the composition of microflora in the analysed alimentary tract segments were examined. The general number of aerobic bacteria, gram-negative bacteria, lactic acid bacteria, Enterobacteriaceae as well as yeast and moulds were considered.

The digestibility of dry matter was not dependent on bird species or the type of diet. The fractions of structural carbohydrates were degraded by cocks to a higher degree than by ganders. On the other hand, the number of aerobic bacteria in ileum and colon was similar in both species of birds (8.7 and 9.2 log cfu×g^-1). No differences were found with regard to SCFA concentration in ileum content between the investigated species, and the cereal grain type did not affect their level. SCFA concentration in colon content was lower when the birds (independently of species) were fed with diets including wheat or maize when compared to the groups receiving other mixtures. It was found that pH reaction in the examined alimentary tract segment content was higher in cocks than in ganders.

The number of aerobic bacteria, Enterobacteriaceae and gram-negative bacteria was positively correlated with SCFA concentration. On the other hand, pH reaction of intestinal content was negatively correlated with the number of all examined types of bacteria. A positive dependence was found between the number of yeasts and moulds and pH value of the birds’ intestinal content.

Key words: non-starch polysaccharides, cereal grains, chickens, geese, bacteria, yeasts and moulds.

INTRODUCTION

Numerous authors [12, 25, 27] noted deterioration of production indexes and utilisation of alimentary components while feeding chicken broilers with large amounts of wheat, barley, oat and rye. The digestibility and absorption of fodder dietary components depends, to a large extent, on the presence of non-starch polysaccharides (NSP). A high content of soluble pentosans and β-glucans (increasing viscosity of the alimentary tract content) in barley, oat and rye grain and, to a smaller degree, in wheat, significantly decreases the digestibility factors of dietary components of the above mentioned cereal grains [2, 8, 34].

The component composition of the diets and the concentration of dietary components influence the intestinal microflora and, thus, the animals’ ability to digest and absorb [13]. As a result of bacterial degradation of carbohydrates, SCFA short-chain fatty acids are formed in the alimentary tract. The SCFA production is conditioned by many factors, mutually influencing one another, among others the number and activity of the alimentary tract microflora and the type of polysaccharides in the diets [28]. Moreover, the availability of dietary components and bacterial flora composition, determining the amount and type of SCFA formed, is of considerable importance [26].

Some authors, including Mattocks [op. cit. after Yu et al., 44] suggest that cellulose complex carbohydrates are not degraded by poultry at all. However, McNab [30], Dawson et al. [10] and Jamroz et al. [13], prove in their experiments that birds partly degraded the structural carbohydrates, including cellulose. Annison et al. [1] as well as McNab [30] found that cellulose complex polysaccharides are digested by micro-organisms in the terminal segments of the birds’ alimentary tract.

Non-starch polysaccharides also influence the increase of the content flow time through the alimentary tract as a result of higher viscosity of their solutions. It mainly depends on the solubility of polysaccharides. The soluble fibre prolongs the time of content flow through the alimentary tract, delays its evacuation and decreases the dietary component absorption. The insoluble fibre, on the other hand, shortens the time of content flow through the alimentary tract, improves the water retention capability and increases the excrement mass in monogastric animals [31].

MATERIALS AND METHODS

The experiment was conducted on 30 eleven-week old ganders of White Italian breed of initial weight of approximately 5.1 kg, and on 60 cocks (Hybro-N) of 7 weeks of age (2.1 kg), which were randomly allocated to five experimental groups for each species. The control group birds (I) were fed with a standard concentrate of nutritive fodder based on ground maize (table 1), while in experimental groups the diets was formed by: wheat (II), barley (III), oat (IV) and rye (V). The tested cereal grain components were administered in such amounts that crude fibre should constitute approximately 2 % of the mixture composition. Rye, whose amount in the diet was limited to 30 % due to the content of antinutritive substances, was an exception.

Table 1. Composition of experimental mixtures

Specification	Feeding groups
	I control	II wheat	III barley	IV oats	V rye
Components (%)
Ground maize	48	10	19	32	27
Ground wheat	10	65	10	16	16
Ground barley	14	-	45	-	-
Ground oats	-	-	-	25	-
Ground rye	-	-	-	-	30
Soybean meal	23	20	21	22	22
Meat-bone meal			2
Limestone			1.2
Dicalcium phosphate			0.5
Fodder salt			0.3
Premix DKA *			1.0
EM MJ×kg-1 **	11.8	11.7	11.3	11.5	11.3
Nutrients (%)
Dry matter	88.4	88.5	88.4	88.5	88.4
Crude protein	18.2	18.3	17.9	18.4	17.9
P - available			0.31
Ca			0.83

*Supplied per kg diet premix content: vitamin A 10000 IU; vitamin D3 2000 IU, vitamin E 20mg, vitamin K, 3 mg, vitamin B1 2.5 mg, vitamin B6 0.4 mg, vitamin B12 0.015 mg, nicotinic acid 25 mg, panthothenic acid 8 mg, folic acid 1.2 mg, choline chloride 450 mg, DL-methonine 1.0 mg, Mn 74 mg, Fe 30 mg, Zn 45 mg, Cu 4 mg, Co 0.4 mg, J 0.3 mg ** Calculated according to the European Tables of Energy Values for Poultry Feedstuffs. [43]

Chickens included in the experiment were previously kept in a floor system, while ganders were kept in the pasture. For this reason, the birds were kept in balance cages for three weeks before commencing the proper physiological experiment. Then, subsequently, two digestibility experiments were conducted, with four-day periods of collection in order to determine the digestibility of the dry matter and of the basic fibrous fractions (crude fibre, NDF, ADF and hemicelluloses).

On completion of the second balance on the first day of the twelfth week of chickens’ life and sixteenth week of ganders’ life, the birds were slaughtered two hours after feeding. Directly after slaughter, samples for microbiological assays were collected from the terminal part (about 25 cm) of ileum and colon. In the remaining intestinal content, pH reaction was determined and then, samples were taken in order to determine SCFA and dry matter. Crude fibre, NDF (Neutral Detergent Fibre) and ADF (Acid Detergent Fibre) were determined in the dehydrated samples of intestinal content.

The content of dietary components in fodder and intestinal content was determined by means of standard methods, according to AOAC [3]. The determination of NDF, ADF and acid detergent lignin (ADL) was conducted with Van Soest method [37]. The amount of hemicelluloses and cellulose was calculated according to the following formulas:

% hemicellulose =  % NDF –  % ADF;  % cellulose =  % ADF –  % ADL.

The dietary fibre (TDF) content with separation into insoluble fraction (IDF) and soluble fraction (SDF) was determined with Asp et al. method [5]. The pH determination of intestinal content were conducted by means of a potentiometric method (pH-meter Medical Mat 1202 SM). The separation of fatty acids was carried out with the application of PYE UNICAM-104 gas chromatograph with 27 cm-column.

The microorganisms in particular segments of the birds‘ alimentary tract were determined by weighing 1 g of the intestinal content into 9 ml of buffered peptone water. The sample prepared in this way was homogenised for two minutes, and then cultures of 0.1 ml of suspension made from subsequent decimal dilutions were put onto solid bacteriological media. The total number of bacteria was determined by means of the colony forming units (cfu) method on TBS medium. The incubation temperature was 37°C, and reading was done after 72 hours. With retaining the same parameters, the lactic acid bacteria were determined with the application of the MRS medium, while Enterobacteriaceae – using VRBG medium (Oxoid). Enterococci were incubated on McConkey medium (incubation temperature of 37°C, reading after 48 hours). Yeast and moulds were determined by applying yeast-peptone-glucose agar medium (Chloramphenicol Yeast Glucose Agar) (the incubation temperature amounted to 25°C, and the reading was taken after 7 days).

The examination results were analysed with statistical methods by means of a two factor variance analysis according to the following model: y_ijk = µ + α_i + β_j + (αβ)_ij + ε_ijk. Where y_ijk – denotes the value of the observed dependent variable, μ – general variable, α_i – diet influence, β_j – influence of bird species, (αβ)_ij – interaction between the type of diet and bird species, ε_ijk – residue error. The numerical material was transformed with the use of the logarithmic method (log₁₀) prior to further analysis. The significance of differences between means values was determined with Tuckey‘s test. Pearson’s correlation coefficients were calculated for basic parameters determined in the intestinal content independently of the examined segment, while their significance was evaluated with t test. The calculations were conducted with Statistica 6.0 [36] software. The experiment results for the main factors (NSP source and bird species) were presented in tables.

RESULTS AND DISCUSSION

The content of structural carbohydrates in the groups where ground maize (I-control) constituted the basic dietary component, wheat (II) and rye (IV), was similar (table 2). The amount of crude fibre was on average 3.6 %, NDF 13.4 %, ADF 4.7 %, ADL 0.9 %, hemicelluloses 8.7  %, cellulose 3.8 % and dietary fibre (14.8 %). The mixture including 45 % of barley (III) was characterised by a higher content of all mentioned components by 10 up to 15 %, and in case of dietary fibre – by about 21 %. The highest concentration of examined structural carbohydrates was noted in the mixture with oat. In comparison to group I, the increase ranged from 31 % in case of crude fibre, up to 59 % in case of cellulose. b-glucan content in the experimental mixtures was similar, fluctuating from 0.5 (group II) up to 0.8 % (group IV), except for group III, in which the level of this fraction was threefold higher and amounted to 1.8 %. Xylose content in the experimental groups was higher by 20 % (V – rye) up to 32 % in the group with 25 % of oat contribution in comparison to the control group, where the content of this component was 2.8 %. The dietary fibre content in the mixtures of group I and II was similar and on average amounted to 14.1 %, while in group III and IV – 18.6 %.

Table 2. Carbohydrates and lignin content (%) in experimental diets

Specification	Feeding groups
	I control	II wheat	III barley	IV oats	V rye
Analysed values
Crude fiber	3.9	3.5	4.3	5.1	3.4
NDF	13.6	13.2	15.5	17.9	13.3
ADF	4.9	4.5	5.6	7.7	4.7
Hemicelluloses	8.7	8.7	9.9	10.2	8.6
ADL	0.8	1.0	0.9	1.2	0.9
Cellulose	4.1	3.5	4.7	6.5	3.8
TDF	14.5	13.8	17.5	19.4	16.2
IDF	13.2	13.2	14.7	17.9	13.9
SDF	1.3	0.6	2.8	1.4	2.3
Calculated values*
Arabinose	2.1	2.3	2.2	1.9	2.4
Xylose	2.8	3.4	3.5	3.7	3.3
b-glucan	0.7	0.5	1.8	0.8	0.6

*Calculated from the data Knudsen K.E.B. [6]

The mean weight of the birds qualified for the experiment was similar, and on average amounted to 3.58 kg. On completion of the second balance, the mean weight of cocks and ganders was 4.72 and 5.17 kg. The mean fodder intake in the experimental groups was uniform, and in the first balance amounted to approximately 205 g/day/animal, while in the other one – 315 g/day/animal. The controlled fodder intake for cocks and ganders was 186 and 223 respectively in the first balance, and 304 and 326 g/day/animal in the second balance.

The dry matter concentration in the birds’ intestinal content proves water metabolism [30] and water binding capability of structural carbohydrates that were not digested earlier [35]. A higher water retention capability is accompanied by high viscosity of NSP solutions [11]. The dry matter content in ileum was from 15.6 % in birds of group III up to 18.5 %, on average, in birds of group I and IV (table 3). The mean content of the analysed parameter in colon was the lowest in group III and V (on average 16.9 %), while in the remaining intestines it amounted on average to 18.4 %. In experiments conducted on various poultry species, Jamroz et al. [20] and Wiliczkiewicz et al. [40] obtained similar values of this parameter regardless of the type of the cereal grain used as the main source of carbohydrates. The concentration of the dry matter in the intestinal content was higher in cocks in comparison to ganders, and amounted to 18.1 and 16.5 % respectively in ileum, while in colon – 19.5 and 16.0 % (p≤0.05). Jamroz et al. [20] obtained similar results for these birds’ species.

Table 3. Concentration of structural substances in dry matter (%) of intestinal contents (Means ±SD)

Specification	Feeding groups					Species of poultry		p value of interaction
	I	II	III	IV	V	chickens	geese
	control	wheat	barley	oats	rye
Dry matter
ileum	18.4 ±2.3	17.1 ±1.2	15.6 ±2.0	18.5 ±2.0	16.9 ±2.6	18.1 ±2.3	16.5 ±1.7	0.435
colon	18.2 ±1.1	18.3 ±3.1	16.9 ±1.6	18.8 ±2.9	16.8 ±2.6	19.5a ±1.6	16.0b ±1.2	0.293
Crude fibre
ileum	12.6 ±3.1	16.9 ±3.3	16.5 ±5.5	15.8 ±2.5	15.6 ±2.1	17.1 ±4.0	13.8 ±2.0	0.935
colon	14.1 ±2.7	17.2 ±2.3	15.6 ±2.0	17.6 ±2.5	14.1 ±2.7	16.1 ±2.8	15.3 ±2.6	0.318
Neutral detergent fibre
ileum	37.1 ±6.6	38.0 ±12.0	40.2 ±3.6	41.9 ±5.4	37.7 ±1.4	41.5 ±6.3	36.5 ±5.5	0.225
colon	37.3 ±9.0	43.6 ±4.7	44.8 ±7.0	38.9 ±6.1	39.1 ±7.2	44.5 ±5.7	37.0 ±6.0	0.786
Acid detergent fibre
ileum	16.3 ±2.5	17.7 ±5.6	16.7 ±1.5	15.4 ±7.6	16.9 ±1.0	18.4 a ±3.2	14.8 b ±4.1	0.234
colon	16.4 ±4.4	19.6 ±1.9	19.5 ±3.8	18.3 ±3.9	17.3 ±3.6	19.9 a ±2.6	16.6 b ±3.5	0.686
Hemicelluloses
ileum	20.8 ±4.2	20.3 ±6.5	23.4 ±2.4	26.5 ±10.8	20.9 ±1.4	23.1 ±3.6	21.6 ±7.7	0.306
colon	20.9 ±5.0	24.1 ±3.6	25.3 ±3.3	20.6 ±2.5	21.8 ±4.5	24.6 a ±3.8	20.4 b ±2.9	0.750

a, b – różnice istotne przy p≤0.05, a, b – significant differences at p≤0.05.

The differences in the concentration of dietary components in the content of individual alimentary tract segments of poultry may indirectly prove their degradation. The lowest content of crude fibre (12.6 %) in ileum content was found in the group of birds receiving the control mixture. In case of the remaining groups of birds, the crude fibre concentration in the content of this intestine segment ranged from 15.6 % up to 16.9 %. In colon, the lowest amounts of crude fibre in the intestinal content was found in group I and V (14.1 %), while the highest – in group II and IV (on average 17.4 %). The crude fibre value in ileum content in cocks was 17.1 %, in ganders – 13.8 %, and in colon – 16.1 and 15.3 % respectively.

The highest NDF concentration (on average 41 %) was found in ileum content of animals taking mixtures with ground barley (III) and oat (IV). A lower and similar concentration was in group I, II and V (37.6 %). The amount of NDF determined in colon content was differended and amounted from 37.3 (I) up to 44.8 % (III). The concentration of this component in the intestinal content of geese was generally lower than in chickens. In ileum of the compared bird species, the mean values amounted to 36.5 and 41.4 % respectively, while in colon – 37.0 and 44.5 %.

The highest ADF concentration was found in ileum content (17.7 %) of the birds fed with ground wheat (II), while the lowest in the group taking ground oat (15.4 %). In colon, the value of this parameter was also the highest in group II, whose main dietary component was constituted by ground wheat (19.6 %), while the lowest (16.4 %) – in the control group. ADF content in ileum and colon of ganders (14.8 and 16.6 %) was lower (p≤0.05) than in cocks (18.4 and 19.9 %).

The percentage content of hemicelluloses in ileum content was the highest in the birds of group III and IV, and amounted to, on average, 24.7 %, while in the remaining experimental groups these values were close to 20.7 %. In colon it was higher (p≤0.05) in chickens (24.6 %) than in geese (20.4 %). The analysed parameter in colon was the highest in group II and IIII (24.1 and 25.3 %), while its lowest values were found in group I and IV (on average 20.7 %). The percentage contribution of hemicelluloses in ileum content of cocks was higher than in ganders and amounted to 23.1 and 21.6 % respectively.

Changes in the dietary nutrients concentration in fodder as well as in ileum and colon content, and their mutual proportions, particularly in relation to poorly metabolised ADF, may result from a varied degree of their degradation in earlier segments of the alimentary tract. Jamroz et al. [23] and Dawson et al. [10] found that NDF in geese at the segment up to ileum, is digested in 32 up to 57 %; ADF in 13 – up to 51 %; cellulose 15 up to 38 %, while hemicelluloses – from 40 up to 66 %. The apparent digestibility coefficient values at the level of colon, found by the same authors amounted to, for NDF, from 32 up to 50 %; ADF 19 up to 52 %, cellulose 22 up to 41 %, and hemicelluloses – from 42 up to 57 %. Rada and Marounek [32] report on the possibility of microbiological breakdown of carbohydrates in birds’ crop (a large number of bacteria and formed SCFA, low pH), while Antoniou et al. [2] – in glandular and muscular stomach.

Apparent digestibility of dry matter and structural carbohydrates

No significant differences were found in apparent digestibility of the dry matter between the dietary groups of birds (table 4), and the mean values ranged from 69.5 % (IV) up to 73.5 % (III). The digestibility coefficients of this component determined in cocks and ganders were similar (71.6 %). These results do not correspond with the values obtained by other authors, who usually obtained lower dry matter digestibility by introducing cereal grain components, increasing NSP content in diets, into birds’ diet, Sue at al. [37]. It may result from the fact that in older birds, which were subject to this experiment, and whose alimentary tract was more mature, the physicochemical parameters of the intestinal content do not have such a big influence on the intestinal and total digestibility of the basic dietary components [39].

Table 4. Apparent digestibility of dry matter and structural substances (%) in birds (Means ±SD)

Specification	Feeding groups					Species of poultry		p value of interaction
	I	II	III	IV	V	chickens	geese
	control	wheat	barley	oats	rye
Dry matter	71.0 ±6.1	73.4 ±3.4	73.5 ±4.2	69.5 ±2.7	70.5 ±2.6	71.5 ±4.0	71.7 ±4.5	0.155
Crude fibre	15.5 A ±8.2	17.4 a ±8.9	23.3 Bb ±10.2	22.7 Bb ±9.7	18.2 ±6.3	22.2 A v8.5	16.7 B ±8.8	0.229
NDF	19.3 Aa ±23.0	29.0 a ±23.0	38.5 Bc ±10.3	33.0 Bbc ±13.5	20.1 Aa ±17.1	37.2 A ±9.9	18.8 B ±21.5	0.403
ADF	14.4 A ±13.5	20.0 A ±13.0	29.0 B ±12.2	31.4 B ±14.8	16.8 A ±12.9	26.2 A ±12.2	18.4 B ±15.8	0.368
Hemiceluloses	53.4 a ±21.6	51.0 ABa ±33.8	64.6 Cb ±18.5	60.1 BCab ±23.9	41.8 Ac ±29.6	75.2 A ±13.1	33.1 B ±18.1	0.183

a, b – significant differences at p≤0,05, A, B – significant differences at p≤0.01.

The results obtained in the conducted experiments prove relatively good structural carbohydrates digestion in the alimentary tract of chickens and geese. Crude fibre was best degraded from diets including ground barley (III) or ground oat (IV) in 23 % on average. Besides, these values were higher in comparison to the mean values determined for the control group 15.5 % (p≤0.01) and the group of birds taking a concentrate mixture with a high content of ground wheat (II) 17.4 % (p≤0.05). NDF and ADF were better degraded by the birds of group III and IV – in 35.8 and 30.2 % on average, and these values were higher (p≤0.01) than in case of animals from the remaining groups. The highest level of hemicellulose digestion (64.6 %) was found in birds of group III, while lower one – in group II and IV (p≤0.01) and I (p≤0.05). Hemicelluloses were worst metabolised – only in 41.8 % by the birds from the group receiving a mixture including ground rye, and this value was significantly lower than in other groups. Summarising, in the conducted experiment, the structural carbohydrates were better degraded by birds receiving the biggest amounts of NSP (III and IV) in their diets. The mean digestibility coefficients of fibrous fractions in cocks amounted to 22.2 % for crude fibre, 37.2 % for NDF, 26.2 % for ADF, and 75.2 % for hemicelluloses, while the same coefficients were lower in ganders by 25, 49, 30 and 57 % (p≤0.01) respectively. Similar relations between the digestibility coefficients of fibrous fractions, proving their more intensive bacterial degradation in the intestinal content of chickens in comparison to geese, were obtained by Jamroz et al. [16].

Microflora of intestinal content

One of the elements of the medium serving for bacterial development in the content of terminal segments of the alimentary tract is constituted, among others, by NSP not metabolised earlier. The general number aerobic bacteria in ileum can be from 5.5 up to 7.3 log cfu×g^-1, Enterobacteriaceae 6.1 up to 6.5 log cfu×g^-1 and Streptococci/Enterococci 3.4 up to 6.4 log cfu×g^-1. Jamroz et al. [17] determined from 4.3 up to 6.0 log cfu×g^-1 Lactobacillus spp., and from 2.8 up to 3.5 log cfu×g^-1 fungi in the content of the terminal segment of ileum. The number of aerobic bacteria determined by Annison et al. [1], Dänicke et al. [9] and Jamroz et al. [18] was from 6.7 up to 8.9 log cfu×g^-1, Lactobacillus spp. from 4.0 up to 8.5 log cfu×g^-1.

Total higher number of bacteria were determined in this study in the content of intestine segments, where a high content of hemicelluloses and an accompanying high level of NDF were found. This relationship was not found only in case of a general number of aerobic bacteria in ileum content (table 5), where the highest number of bacteria (9.04 log cfu×g^-1) was observed in the birds receiving concentrate with ground wheat (II), while in the remaining groups the mean values were similar and amounted to: from 8.50 log cfu×g^-1 (V) up to 8.69 log cfu×g^-1 (IV). The lowest average values were noted in colon content of the birds taking ground oat (8.95) and ground wheat (9.04 log cfu×g^-1), while the highest – in the birds of group III and V (9.41 and 9.50 log cfu×g^-1). The general number of aerobic bacteria determined in ileum content of the birds was slightly higher in cocks in comparison to ganders, and the values were 8.76 and 8.57 log cfu×g^-1 respectively, while in colon they were higher – 9.29 and 9.17 log cfu×g^-1.

Table 5. Amount of microorganisms (log cfu×g-1) of intestinal content (Means ±SD)

Specification	Feeding groups					Species of poultry		p value of interaction
	I	II	III	IV	V	chickens	geese
	control	wheat	barley	oats	rye
Total number of aerobic bacteria
ileum	8.51 ą1.53	9.04 ±1.13	8.59 ±0.52	8.69 ±0.81	8.50 ±0.63	8.76 ±0.57	8.57 ±1.18	0.996
colon	9.25 ą0.76	9.04 ą1.43	9.41 ą1.22	8.95 ą1.20	9.50 ą1.02	9.29 ą0.75	9.17 ą1.32	0.744
Lactic acid bacteria
ileum	6.67 ±1.99	8.85 ±1.60	7.21 ±2.22	6.96 ±1.32	6.18 ±1.80	6.64 ±2.17	7.71 ±1.39	0.450
colon	7.01 ±1.86	6.69 ±1.61	7.72 ±2.59	6.68 ±1.67	7.77 ±0.94	6.62 ±1.59	7.73 ±1.67	0.470
Gramnegative bacteria
ileum	4.95 ±0.65	5.45 ±0.57	6.03 ±0.56	5.33 ±0.70	5.26 ±0.24	5.22 ±0.71	5.59 ±0.49	0.501
colon	5.20 a ±0.76	5.72 ab ±0.90	5.82 b ±0.71	5.66 ab ±0.64	5.61 ab ±1.57	5.42 ±0.96	5.79 ±0.82	0.682
Enterobacteriaceae
ileum	4.27 ab ±0.48	4.33 ab ±0.32	4.63 b ±0.60	3.90 ac ±0.94	3.83 c ±0.67	3.71 ±0.47	4.68 ±0.35	0.127
colon	4.72 ±0.20	4.75 ±0.85	4.60 ±1.07	4.38 ±0.29	4.42 ±0.29	4.43 ±0.59	4.72 ±0.60	0.204
Yeasts and moulds
ileum	3.69 a ±0.51	4.62 b ±0.22	4.00 ab ±0.00	4.74 b ±0.69	4.35 ab ±0.43	4.42 ±0.55	3.94 ±0.69	0.000
colon	4.15 ±0.30	4.15 ±0.17	4.44 ±0.27	4.53 ±0.66	4.12 ±0.24	4.38 ±0.48	4.18 ±0.21	0.016

a, b – significant differences at p≤0.05.

The mean number of lactic acid bacteria was comparable in the content of ileum and colon, the mean values for both segments of intestines in chickens were 6.63 log cfu×g^-1 and in geese 7.72 log cfu×g^-1. The highest mean number of these bacteria in ileum content was observed in group II of birds (8.85 log cfu×g^-1), while the lowest (6.18 log cfu×g^-1) – in the animals receiving ground rye in their diet (V). The highest number of lactic acid bacteria in colon content was found in group III and V, 7.75 log cfu×g^-1, while the lowest – in group II and IV (6.69 log cfu×g^-1).

A relatively low number of gram-negative bacteria was determined in the birds of the control group (4.95 log cfu×g^-1), while the highest in the birds fed with a mixture including of ground rye 6.03 log cfu×g^-1. The mean number of these bacteria in colon content in this group (III) was also the highest (5.82 log cfu×g^-1), and in comparison to the mean of the control group of birds 5.20 log cfu×g^-1 it was significantly higher (p≤0.05). The mean number of gram-negative bacteria determined in ileum content of cocks and ganders amounted to 5.22 and 5.59 log cfu×g^-1, and in colon 5.42 and 5.79 log cfu×g^-1.

The number of bacteria of Enterobacteriaceae group in ileum content of chickens and geese amounted to 3.71 and 4.68 log cfu×g^-1, and in colon 4.43 and 4.72 log cfu×g^-1. The lowest mean number of these bacteria was found in group V of the birds (3.83 log cfu×g^-1), and it differed (p≤0.05) in comparison to the mean values in group I, II and III. In the group of birds fed with a mixture with a large contribution of ground barley, the number of Enterobacteriaceae was 4.63 log cfu×g^-1 and it was significantly higher in comparison to the mean value of group IV (3.90 log cfu×g^-1).

Hűbener et al. [13] found in chickens of 42 days of age that the higher number of lactic acid bacteria in ileum content when using mixtures including wheat and rye as the basic source of structural carbohydrates in comparison to maize, while lower numbers in case of Enterobacteriaceae. Apajalahti et al. [4] prove that the substitution of ground wheat with ground rye in the mixtures for chickens results in a significant decrease of Lactobacillus spp. bacteria number in ileum content.

Jamroz et al. (2002e), when substituting ground maize with wheat and barley in the mixtures for chickens, found a increasing concentration of lactic acid bacteria in caecum content (p≤0.05) on the 21st day of life, (p≤0.01). These authors [24], while using similar concentrates with regard to component content in another experiment, observed a higher (p≤0.05) number of Lactobacillus spp. bacteria in ileum content when feeding 41-day old chickens with wheat-barley mixture (6.0 log cfu×g^-1) in comparison to maize (4.7 log cfu×g^-1).

The total number of fungi determined in the birds’ ileum content was 4.42 in cocks and 3.94 log cfu×g^-1 in ganders, while in colon it was 4.38 and 4.18 log cfu×g^-1 respectively. The lowest number of fungi was determined in ileum content of the control group birds (3.69 log cfu×g^-1), and there were significantly high (p≤0.05) of these microorganisms in group II and IV (4.62 and 4.74 log cfu×g^-1). Their mean amount in colon content ranged from 4.12 up to 4.53 log cfu×g^-1, and no significant differences were found between the groups. Jamroz et al. [19] determined higher (p≤0.01) number of fungi in the content of chickens’ caecum, when feeding them with a concentrate of high content of wheat and rye (4.0 log cfu×g^-1) in comparison to a standard mixture including ground maize (2.2 log cfu×g^-1). While investigating similar mixtures in 41-day old chickens, Jamroz et al. [24] determined on average 3.3 log cfu×g^-1 of fungi in ileum content without proving the cereal grain effect on this parameter.

SCFA concentration and pH value of the intestinal content

SCFA concentration (table 6) in the intestinal content of the birds from individual dietary groups was similar, and in case of ileum it ranged from 11.1 (IV) up to 12.8 mmol×kg^-1 (I). The content of SCFA in colon was more diversed and varied between 20.9 (II) and 38.5 mmol×kg^-1 (IV); however, due to the significant variability between particular measurements, the differences between the mean values were not confirmed statistically. SCFA content in the intestinal content of cocks and ganders was similar, and in case of ileum amounted to 11.0 and 13.0 mmol×kg^-1, while in case of colon – 29.2 and 27.0 mmol×kg^-1. Also Jamroz et al. [14, 22] observed similar SCFA values in the content of ileum and colon of these poultry species. A higher concentration of SCFA would prove greater activity of the microorganisms in the intestinal content causing NSP degradation and fermentation. Jamroz et al. [21], in another experiment, when feeding broiler chickens with mixtures whose main components were constituted by ground wheat and ground barley and both in relation 1:1, observed similar SCFA values in ileum content, oscillating around 10 mmol×kg^-1. Hűbener et al. [13], on the other hand, obtained higher SCFA values in jejunum and caecum content of the chickens fed with wheat/rye mixture in comparison to maize, while in ileum content this dependence was opposite.

Table 6. Short-chain fatty acids concentration and pH value of intestinal contents of birds (Means ±SD)

Specification	Feeding groups					Species of poultry		p value of interaction
	I	II	III	IV	V	chickens	geese
	control	wheat	barley	oats	rye
SCFA (mmol×kg-1)
ileum	12.8 ±2.4	12.3 ±2.3	12.4 ±2.9	11.1 ±1.3	11.4 ±1.6	11.0 ±1.7	13.0 ±2.2	0.076
colon	22.6 ±7.1	20.9 ±4.5	30.3 ±9.2	38.5 ±15.0	28.0 ±11.2	29.2 ±12.8	27.0 ±10.4	0.081
pH value
ileum	6.81 ±0.45	6.99 ±0.26	6.80 ą0.67	7.08 ±0.22	6.80 ą0.44	7.00 ±0.35	6.79 ±0.50	0.789
colon	6.80 ±0.51	6.96 ±0.33	6.54 ±0.41	7.11 ±0.26	6.78 ±0.55	6.93 ±0.40	6.75 ±0.49	0.441

The pH value of ileum content was higher in the groups of birds that were fed with concentrates including ground wheat (6.99) and oat (7.08) in comparison to ground maize, barley and rye, where the pH value was on average 6.80. The lowest pH reaction in colon was determined in group III (6.54) and V (6.78), while the highest in group II (6.96) and IV (7.11). The pH values in the intestinal content of geese were only slightly lower than in chickens and amounted to 7.00 and 6.79 in ileum and 6.93 and 6.75 in colon, in cocks and ganders, respectively.

Mathlouthi et al. [29], when feeding chickens with a concentrate including maize, found higher (p≤0.01) pH values in ileum in comparison to the diet including wheat and barley. Jamroz et al. [15], while using concentrates including ground wheat and barley in the chickens’ diet, obtained lower pH values (p≤0.05) in ileum content – 6.0, and in colon – 5.8 on average, in comparison to mixtures with a high content of ground barley (6.7). Jamroz et al. [20], when using a mixture including ground maize, wheat and barley in feeding broiler chickens, recorded a lower pH value in caecum content, and higher in colon than in birds fed with a mixture including 40 % of triticale. Similarly to the present study, Jamroz et al. [14] found slightly lower pH reaction in the content of ileum and colon of geese than of chickens.

The correlation coefficients were calculated for the parameters determined in the intestinal content, independently of the examined segment. No significant dependencies were found between the content of fibre fraction in the intestinal content and SCFA concentration, pH reaction and the number of microorganisms (table 7). The only exception was a significant positive correlation noted between the amount of yeasts and moulds and the concentration of hemicelluloses (r = 0.407).

Table 7. Correlation coefficients of estimated parameters of intestine contents

Parameters	SCFA	pH	Total aerobic count	Enterobac-teriaceae	Lactic acid bacteria	Gram-negative	Yeasts and moulds
Crude fibre	-0.013	0.123	0.110	-0.293	-0.307	-0.212	-0.320
NDF	0.282	-0.071	0.224	-0.071	-0.205	-0.063	0.323
ADF	0.248	-0.109	0.329	-0.174	-0.286	0.045	0.081
Hemicelluloses	-0.014	-0.012	0.206	0.017	-0.083	-0.133	0.407**
SCFA	-	-0.044	0.733**	0.386*	0.014	0.453**	0.145
pH		-	-0.285	-0.351*	-0.471**	-0.654**	0.377*
Total aerobic count			-	0.296	0.373*	0.441**	0.225
Enterobacteriaceae				-	0.369*	0.581**	0.038
Lactic acid bacteria					-	0.383*	0.105
Gramnegative						-	-0.242

*correlation coefficients significant at p≤0.05; **correlation coefficients significant at p≤0.01

Similarly to earlier studies [42], a positive interdependence was found between all determined types of bacteria and SCFA concentration, while a negative one – with regard to pH reaction. A positive dependence between the general number of aerobic bacteria and lactic acid bacteria also proved to be significant. No negative influence of bacteria on yeast and moulds was found.

SUMMARY

The introduction of oat grain into concentrates for adult cocks and ganders, instead of maize used as a standard, resulted in the increase of cellulose complex components and dietary fibre, and in case of the introduction of barley – the additional result was the increase of the amount of ß-glucans.

Irrespectively of the type of the cereal grain used, a lower concentration of the dry matter and structural carbohydrates was found in the intestinal content of geese when compared to chickens.

The apparent digestibility coefficients of the dry matter were at a similar level, regardless of bird species, in all experimental groups.

The non-starch polysaccharides were digested significantly better by the birds of the groups fed with diets including higher amounts of them.

The structural carbohydrates factions were significantly better degraded by cocks than by ganders.

The number of aerobic bacteria in the ileum and colon content of both poultry species was similar. A higher number of lactic acid bacteria, gram-negative bacteria and Enterobacteriaceae were observed in ganders than in cocks. Yet, a bigger number of yeast and moulds were found in chickens.

The SCFA concentration in ileum content of chickens and geese was similar, and the type of the cereal grain used did not influence their concentration, either. The level of these acids in colon content was lower in birds receiving maize or wheat in the feeding mixture, while compared to the animals fed with diets including the remaining cereal grains tested.

The pH value of the examined intestine segments was found to be higher in cocks than in ganders.

The number of aerobic bacteria, Enterobacteriaceae and gram-negative bacteria was significantly positively correlated with the SCFA concentration. The negative correlation coefficients were found for all the examined types of bacteria, while a positive correlation was observed for yeast and moulds in comparison to the pH reaction.

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Andrzej Wiliczkiewicz
Department of Animal Nutrition and Feed Quality,
Wrocław University of Environmental and Life Sciences, Poland
Chełmonskiego 38D, 51-630 Wrocław, Poland
phone: (0-71) 320 58 35
email: wiliczkiewicz@op.pl

Janusz Orda
Department of Animal Nutrition and Feed Management, Faculty of Biology and Animal Science, Wrocław University of Environmental and Life Science, Poland
Chełmońskiego 38 C
51-630 Wrocław, Poland
Phone +48 71 32-05-837
fax: +48 71 32-05-845

Dorota Jamroz
Department of Animal Nutrition and Feed Management,
Wrocław University of Environmental and Life Sciences, Wrocław, Poland
Chełmońskiego 38 C, 51-631 Wrocław, Poland
phone: +48 71 3205 828
fax: +48 71 3205 965
email: dorota.jamroz@up.wroc.pl

Jolanta Skorupińska
Department of Animal Nutrition and Feed Quality,
Wrocław University of Environmental and Life Sciences, Poland
Chełmonskiego 38D, 51-630 Wrocław, Poland
phone: (0-71) 320 58 35

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