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

Abstract This study was conducted to investigate the effects of dietary supplementation of L-glutamine and the synergistic effects between glutamic acid of wheat and glutamine on the performance, carcase characteristics and intestinal morphometry in guinea fowl chickens fed with corn–soybean meal–wheat-based diets. A total of 288 one-day-old guinea fowl chicks (Numida meleagris) were used in a completely randomised design with six treatments, six replicates and 8 male chickens per replicate. The treatments were as follows: (1) corn–soybean meal-based diet (control), (2) corn–soybean meal–wheat-based diet, (3) treatment 1 containing 0.5% L-glutamine, (4) treatment 1 containing 1% L-glutamine, (5) treatment 2 containing 0.5% L-glutamine and (6) treatment 2 containing 1% L-glutamine. The results showed that the body weight gain (BWG) was higher in glutamine-supplemented treatments and the best feed conversion ratio (FCR) was observed in treatment 2 with 0.5% glutamine supplementation (p？<？.05). The chicks fed by diets containing glutamine supplement showed a higher live weight and percentage of breast, thigh and wings compared to glutamine-free diets, whereas the highest percentage of liver and heart observed in treatment 1 and the highest percentage of gizzard in treatments 1 and 2 (p？<？.05). The length and the width of villi and crypt depth in all three parts of the small intestine (duodenum, jejunum and ileum) were higher in glutamine-based treatments compared to glutamine-free treatments (p？<？.05). Also, the addition of wheat to diet had no negative effects on the mentioned parameters; moreover, the 0.5% L-glutamine supplement in wheat–corn–soybean diets improved performance, carcase characteristics and intestinal morphometry