Gastrointestinal Tract Of Poultry Research Articles

Enzyme supplements in broiler chicken diets: in vitro and in vivo effects on bacterial growth

AbstractIncreasing the growth performance of broiler chickens by supplementing their diets with exogenous enzymes can also contribute to positive changes in gut health. In this respect the growth of various bacteria normally associated with the gastrointestinal tract of poultry was assessed in vitro using a medium containing arabinoxylan, β‐glucan, guar gum and raffinose and their corresponding enzymes. Overall, enzymes releasing the largest amounts of free sugars yielded the largest increase in bacterial numbers. Accordingly, β‐glucan and raffinose treated with their respective enzymes promoted the largest number of bacterial types, reaching a minimum of 1.0 log10 population within 6 h at 40 °C. A broiler chicken growth trial was also conducted using wheat‐, barley‐ and corn‐based diets with and without enzyme and probiotic addition. Escherichia coli, coliforms, enterococci and aerobic and anaerobic sporeformers were monitored for growth in both the caecum and ileum. Enzyme supplementation reduced E. coli levels in the caecum of broilers fed wheat‐ or corn‐based diets. A further reduction in E. coli numbers was observed in broilers fed the same diets supplemented with a combination of enzyme and probiotic. Enzyme supplementation had much less of an effect on microbial populations in the ileum. Inclusion of probiotics reduced E. coli levels in the caecum and ileum but only in broilers fed wheat‐ and corn‐based diets. Anaerobic spore levels in the ileum increased in all diets containing probiotic. Overall, inclusion of enzymes or probiotics exhibited mixed effects on gut bacteria, depending on the nature of the carbohydrate source and enzyme. Copyright © 2007 Society of Chemical Industry

Characterisation of a novel plasmid p9785S from Lactobacillus johnsonii FI9785

Lactobacillus johnsonii FI9785, a strain originally isolated from poultry gastrointestinal tract for its probiotic function as a competitive excluder of pathogens, was found to contain two cryptic plasmids of 3.5 and 25.6 kb. Nucleotide sequence analysis of the entire small plasmid, designated p9785S (3471 bp), indicated a G + C content of 35.8%, and revealed two open reading frames (orfs). The product of orf1 exhibited similarity to the relaxases of mobilizable plasmids, whereas the product of orf2 displayed significant homology to replication proteins of plasmids which use the rolling circle mode of replication. A conserved double-strand origin of replication was also present in p9785S. A definite minus origin was not identified although a region with extensive intrastrand base pairing potential was revealed. A 1.4 kb fragment encoding the chloramphenicol resistance gene was cloned into p9785S and the resulting vector, pFI2431, was stably maintained when introduced into the parent Lactobacillus cells.

Portal Absorption of Feed Oligo-peptides in Chickens

The effect of duodenal infusion with feed oligo-peptide solution on portal absorption of amino acids was investigated in poultry under unanaesthetized conditions. Four peptide solutions were used in the experiment: enzymatic hydrolysates from fish meal, soybean meal, cottonseed meal and rapeseed meal proteins with average molecular weights less than 3,000 Da and 1,000 Da, respectively. Intestinal absorptions of these oligo-peptide solutions were compared by determining the concentration of free amino acid (FAA) in portal blood after the duodenal administrations of oligo-peptide solutions. Absorptive intensity and balance were used to estimate the intestinal absorption rate of amino acids. The absorptive intensities of amino acids were highest for the fish and soybean meal oligo-peptides. The ratios of amino acids absorbed in the portal blood from fish and soybean meal oligo-peptides were more similar to the composition of the infused amino acids than that observed from the cottonseed and rapeseed meal oligo-peptides. A positive correlation was found between absorption rate and proportion of PAA in the oligo-peptides. The higher absorption rate could be contributed to the higher proportion of peptide bound amino acids (PAA). The results suggest that fish and soybean meal protein are significantly more easily hydrolyzed into oligo-peptides (p<0.05) in the gastrointestinal tracts of poultry and as such can be utilized more effectively by body tissues. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 9 : 1277-1280)

Effect of different levels of bacterial probiotic on broilers performance

The microbial populations in the gastrointestinal tracts of poultry play a key role in normal digestive processes and in maintaining animal health. Disease- and stress-induced changes in the physicochemical environment in the gastrointestinal tract, or simple changes in feed management practices can significantly influence the microbial populations and their effects on animal performance and health. In the last five decades, increased knowledge of the factors that influence the activities of microorganisms in the alimentary tract has helped to define the critical role of these symbiotic organisms. Probiotics, competitive exclusion and direct-fed microbial feed supplements can be used as a strategic tool for managing these microbial populations. The aim of this trial was study of effect of different levels of bacterial probiotic on broilers performance and some of blood factors.

The efficacy of phytase in corn-soybean meal-based diets for laying hens

Microbial phytase hydrolyzes poorly degradable vegetable phytate P in the gastrointestinal tract of poultry; thereby increasing the availability of organic P to an extent that remains to be established. For this purpose, the P equivalency value of phytase in corn-soybean meal layer diets was assessed in three experiments (two short-term absorption studies and one performance trial lasting a complete production period). In the first absorption study, two basal diets containing 30 or 40 g Ca/kg diet were supplemented with either phytase [0, 250, or 500 phytase units (FTU)/kg diet] or with monocalcium phosphate (MCP; 0, 0.5, or 1.0 g P/kg diet) and fed to layers from 20 to 24 wk of age. The ileal absorption of Ca and P was measured during the last week. It was shown that 250 FTU/kg diet hydrolyzed an amount of phytate P that was equivalent to 1.3 g P from MCP. At the highest phytase inclusion level (500 FTU/ kg diet), a lower value of equivalency was observed, as P absorption was almost maximal at the lower level of phytase inclusion (250 FTU/kg diet). Phytase hydrolyzed phytate-bound P effectively at both Ca levels, although this degradation was significantly reduced by 12 percentage units at the higher dietary Ca level. The second absorption study, used 0, 250, and 500 FTU phytase/kg diet and 0 and 1.0 g P/kg diet of MCP. All diets were standardized at 35 g Ca/kg diet. The ileal absorption of Ca and P was determined at 24 and 36 wk of age. These values were significantly reduced in 36-wk-old hens compared to 24-wk-old hens. At 24 wk of age, phytic acid P degradation was significantly improved with increasing levels of phytase up to the maximum inclusion level of 500 FTU/kg diet (maximum phytic acid-P degradation at the end of the small intestine was 66%). In this experiment, the dose of 250 FTU/kg diet was equivalent to 0.8 g MCP-P. In Experiment 3, either phytase or MCP-P was added to a corn-soybean meal layer diet, containing 40 g Ca/kg diet and 3.6 g P/kg diet, at levels of 0, 100, 200, and 300 FTU/kg or levels of 0, 0.3, 0.6, and 0.9 g MCP-P/kg, respectively. Production performance was measured from 18 to 68 wk of age. Diets were consumed ad libitum. Growth, production performances (except kilograms of feed per kilogram of egg), and tibia parameters were significantly improved by dietary supplementation of the negative control diet with either phytase or MCP-P. Growth, egg production, and feed conversion ratio of the hens from the supplemented groups remained good throughout the experiment. No phytase dose effects on the production characteristics or tibia parameters were observed, indicating that the P requirements of the laying hens were met throughout the production period even at the lowest level of supplementation.

Hydrolysis of galactooligosaccharides by commercial preparations of α‐galactosidase and β‐fruetofuranosidase: Potential for use as dietary additives

AbstractIn vitro and in vivo studies were conducted with six commercial enzyme preparations (SP249, Energex, Rohament CW, Novozyme 230 and crude α ‐galactosidase) to determine their effectiveness in hydrolysing galactooligosaccharides from soya bean and canola meal in the gastrointestinal tract of poultry. The use of the enzyme invertase to enhance galactoside hydrolysis was also studied. A wide range of α ‐galactosidase activity was observed in vitro, with crude α‐galactosidase from Mortirella vinacea and Novozyme 230 preparation showing the highest activity values of 4.3 and 1.5 nkat mg−1, respectively. All preparations with the exception of crude α‐galactosidase showed invertase activity which is known to convert raffinose and stachyose to the corresponding di‐and trisaccharide, melibiose and manninotriose. Although the activity of invertase was highest on sucrose, the Novozyme 230 preparation showed activity values of 4.2 and 2.3 nkat mg−1 toward raffinose and stachyose substrates, respectively. De novo synthesis of raffinose was observed when soya bean meal, canola meal or pure sucrose and galactose were incubated with certain enzyme preparations (ie Energex). In general, preparations possessing hydrolytic activity towards galactooligosaccharides showed very little synthesis of raffinose while preparations capable of generating raffinose were very weak in the hydrolysis of galactooligosaccharides. The best result in terms of galactooligosaccharide in vitro hydrolysis of canola and soya bean meal was obtained with a combination of α‐galactosidase and invertase. In the in vivo study with caecectomised hens, hydrolysis of galactooligosaccharides averaged 88% when crude α‐galactosidase (2 g kg−1) and invertase (1 g kg−1) were added to laying, hen diet containing 200 g soya bean meal per kilogram. A problem identified in the current study was that minerals such as calcium phosphate and calcium carbonate common in poultry diets inhibit the hydrolysis activity of α‐galactosidase, indicating that high levels of activity would be required to yield a response in practical poultry feeding.

OPTIMIZATION OF THE HISTOGENESIS OF THE GASTROINTESTINAL TRACT ORGANS IN CHICKEN EMBRYOS DURING AEROSOL TREATMENT OF HATCHING EGGS WITH BIOLOGICALLY ACTIVE SUBSTANCES

The pre-incubation treatment of eggs of the Ross 308 cross-country with a composition consisting of colamine, succinic acid, serine and vitamin B6 had a positive effect on the incubation biocontrol parameters, antioxidant status and histogenesis of some internal organs of the poultry gastrointestinal tract. Thus, the output of chickens in the experimental batch exceeded the control by 2.47%, and the hatchability by 2.23%. The thermogenesis of chickens from the experimental group was also better; the temperature was significantly higher by 0.7-1.3 ° C (p &lt;0.05, p &lt;0.01) as compared with the control. The antioxidant properties of this composition contributed to a decrease in the ORH level by 2.5 times (p &lt;0.05), (MDA) - by 1.3 times (p &lt;0.05), with an increase in the peroxidase activity by 17.65%, SOD- 1.6 times (p &lt;0.01), respectively, relative to the control. internal organs for histological examination were taken. The decrease in the anomalous intensity of free-radical reactions and, as a result of lipoperoxidation, had a positive effect on the histoarchitecture of the muscular and glandular stomachs. Thus, a tendency to an increase in the thickness of the mucous membrane of the muscular stomach by 16.6% was recorded, as well as its cuticle significantly 1.4 times (p &lt;0.05), glandular - 1.2 times (p &lt;0.01) relative to control. These data allow us to conclude that the study of the histological characteristics of the stomachs in chickens at the age of day is an important marker of their future adaptive capacity in postembryogenesis. The literature suggests that increasing the thickness of the glandular mucosa will contribute to better digestion of feed, the viability of intramural regulatory processes, intestinal microbiocenosis and other functions of the digestive system as a whole.