Effects of dietary L-glutamine supplement on performance, characteristics of the carcase and intestinal morphometry in guinea fowl chickens (Numida meleagris)

Effects of glutamine supplementation on the growth performance, antioxidant capacity, immunity and intestinal morphology of cold-stressed prestarter broiler chicks

BACKGROUND

Cold stress has important effects on the growth and production of broiler chickens. Glutamine (Gln) is a conditionally essential amino acid that plays an important role in promoting intestinal development and enhancing immune function. The aim of this study was to investigate the effects of Gln supplementation on the growth performance and health of cold-stressed prestarter broiler chicks.

METHODS AND RESULTS

A total of 375 1-day-old male SZ901 broilers were randomly divided into five groups (CON, CS, GLN1, GLN2, GLN3). Birds in the CON and CS groups were provided with normal drinking water, while the GLN1, GLN2 and GLN3 groups were provided with water supplemented with 0.4%, 0.8% and 1.2% Gln, respectively. At d7, birds in groups CS, GLN1, GLN2, and GLN3 were stressed at 12 ± 1 ℃ for 12 h. The results showed that cold stress significantly decreased the growth performance, serum antioxidant capacity and antibody concentrations, small intestine villus structure, and increased the gene expression of intestinal inflammatory factors of broiler chicks compared with the CON group (P < 0.05). Compared with the CS group, Gln supplementation exhibited increased growth performance, serum antioxidant capacity and antibody concentrations, gene expression levels of intestinal tight junction protein, villus height and villus height to crypt depth ratio (V/C) of small intestine, and decreased mRNA expression level of intestinal inflammatory factors (P < 0.05).

CONCLUSIONS

Gln supplementation ameliorated the impact of cold stress to a large extent as it promoted the development of the intestine and immune system and enhanced the antioxidant enzyme system in cold-stressed prestarter chicks.

Evaluating the effects of dietary glutamine on performance, carcass traits, blood biochemistry, and intestine morphology in laying quail

This study investigated the effects of dietary glutamine (Gln) supplementation on the performance, carcass characteristics, blood biochemistry, intestinal morphology, and gut microbiota of laying quail over a 12-week period, with analyses conducted after 6 and 12 weeks of supplementation. Seven-week-old dual-purpose female quails at the onset of laying were assigned to diets containing 0% (control), 0.5%, 1%, or 1.5% Gln. Performance metrics included laying rate, daily feed intake, and feed efficiency. Supplementation with 0.5% Gln significantly enhanced the laying rate after 12 weeks; daily feed intake and feed efficiency varied over time but were not consistently affected by Gln. Breast muscle weight was highest in quail supplemented with 1.5% Gln after 6 weeks. Blood serum analyses showed that total protein and albumin concentrations were highest in quail receiving 0% and 1% Gln after 12 weeks, while supplementation with 0.5% Gln decreased triacylglycerol levels after 12 weeks. Glucose and creatinine levels varied with Gln supplementation and between the two time points; enzyme activities (alanine transaminase, alkaline phosphatase, and gamma-glutamyl transpeptidase) were affected by both Gln dose and length of supplementation. Intestinal morphology was significantly influenced by Gln dose and supplementation period. The longest villi were observed in quail supplemented with 1% Gln after 6 weeks, decreasing by 12 weeks. The widest villi were recorded in quail receiving 1.5% Gln after 6 weeks, with villus width decreasing over time. Crypt depth varied significantly, with the deepest crypts observed at 6 weeks in quail supplemented with 1% and 1.5% Gln, becoming shallower after 12 weeks. Microbial analysis of digesta samples revealed Lactobacillaceae as the predominant bacterial family, followed by Enterobacteriaceae and genera including Streptococcus and Staphylococcus. Overall, dietary Gln supplementation influenced performance, carcass characteristics, blood biochemical parameters, intestinal morphology, and gut microbiota composition in laying quail, with effects varying between 6 and 12 weeks of supplementation. These findings suggest that Gln supplementation has the potential to enhance quail performance and health over time.

Dietary L-glutamine affects eggshell quality in the post-peak laying period

In the current study the hypothesis that 1.0% dietary inclusion of glutamine (Gln), a conditionally essential amino acid that influences protein synthesis and shows anti-osteoporotic effect, can influence eggshell quality was tested on laying hens in the post-peak laying period. A 30-week-old Bovans Brown hens were randomly assigned to control group or group supplemented with Gln in the form of alpha-ketoglutarate (10 g/kg) with 12 replicate cages (2 hens/cage) in each group. The experimental period lasted for 30 weeks, from the 31st to the 60th week of age of hens, when eggs were collected and selected eggshell quality indices were determined. While Gln supplementation had no effect on egg geometry and eggshell cracking force, the analysis of eggshell quality showed an increase of the eggshell thickness (P<0.01), porosity (P<0.01), eggshell specific surface (P<0.001) and positive changes in other mechanical parameters (decrease of eggshell stiffness and Young’s modulus, P<0.05 and P<0.01, respectively; increase of work needed to crack the eggshell, P<0.05). Changes in eggshell mineral composition, including an increase of Ca content (P<0.001), were also observed. In conclusion, the current study showed a beneficial effect of Gln on the eggshell thickness, calcification, and some mechanical parameters.

The Effect of L-Glutamine on Basal Albumen and Yolk Indices, and Albumen Amino Acids Composition

Simple Summary

At present, with increased consumers’ focus on eating healthy, it is expected that egg protein content and amino acids profile are among the components of eggs that play critical roles in egg selection. Thus, this research investigated the effect dietary L-glutamine supplementation has on basal albumen and yolk indices as well as albumen protein amino acid profile. The study shows a potential role of L-glutamine supplementation for enhancing nutritional values of eggs by the decrease of albumen lipid content and the change of amino acid profile.

Abstract

The current study tested the hypothesis that 1.0% dietary inclusion of L-glutamine (Gln), an non-essential amino acid that influences protein synthesis, can improve internal egg quality, including amino acids profile. Thirty-week-old Bovans Brown laying hens in their middle laying period were assigned to one of the two experimental groups (12 replicate cages, 2 hens/cage) with Gln in the form of alpha-ketoglutarate (10 g/kg) or without Gln inclusion. The experimental period lasted for 30 wks, from the 31st to the 60th week of age of hens, when eggs were collected and selected egg quality indices were determined. Gln supplementation had no effect on albumen and egg yolk share, albumen and yolk basal indices and composition, including yolk cholesterol content. However, Gln decreased the lipid content of the egg albumen (p < 0.001), and influenced albumen amino acid profile, increasing content of asparagine (p < 0.05), phenylalanine (p < 0.05), proline (p < 0.001), tryptophan (p < 0.01), and tyrosine (p < 0.05). In conclusion, the study shows a potential role of Gln supplementation for enhancing nutritional values of eggs by lower lipid content and higher amino acid profile.

Positive Influence of a Probiotic Mixture on the Intestinal Morphology and Microbiota of Farmed Guinea Fowls (Numida meleagris)

To understand the effectiveness of a probiotic mixture on intestinal morphology, mucus layer composition, and cecal microbiota diversity, 40 10-day-old Guinea fowls (Numida meleagris) were assigned to two groups: the control group (C), receiving drinking water, and the treated group (P), receiving water plus a commercial multi-strain probiotic (Slab51®, 2 × 10¹¹ CFU/L). Birds were slaughtered after 4 months, and the intestines were collected. Samples from the duodenum, ileum, and cecum were processed for morphological and morphometric studies, and conventional glycohistochemistry. Cecal samples were also used to assess the microbiota by 16S metataxonomic approach. Group P showed significant increase in the villus height (p < 0.001 in the duodenum and p < 0.05 in the ileum and cecum), villus width (p < 0.05 in all investigated tracts), depth of crypts (p < 0.001 in the duodenum and cecum; p < 0.05 in the ileum), and goblet cells per villus (p < 0.001 in all investigated tracts) compared with group C. Cecal microbiota of the birds varied considerably and comparing the relative abundance of the main observational taxonomic units (OTUs), a positive enrichment of several beneficial taxa, such as Oscillospira, Eubacterium, Prevotella, and members of the Ruminococcaceae, was observed. The enrichment of those taxa can improve microbiota stability and resilience facing environmental stresses, enhancing its resistance against invading pathogens. Ruminococcaceae, which represent the most important taxon in both groups, and Prevotella have a key role in the gut physiology due to the production of short-chain fatty acids (SCFAs), which are a vital energy source for enterocytes, improve glucose metabolism, and exert an overall anti-inflammatory effect. Probiotic administration enriches the presence of Coprococcus, Oscillospira, and Eubacterium taxa that produce butyrate, which exerts a beneficial effect on growth performance, structure of villi, and pathogen control and has anti-inflammatory properties too. This study indicates that Slab51® supplementation positively affects the morphology and microbiota diversity of the guinea fowl intestine.