| Summary: | SUMMARY: The objective of this work was to study the effect of β-mannanase supplementation in diets of broilers challenged with Eimeria sp. on performance, intestinal morphology, and immune profile. A total of 320 male chicks were housed in a completely randomized design in 2 × 2 factorial scheme (with and without β-mannanase and with and without challenge with coccidiosis vaccine at 14 d of age). Feed intake, a week after the experimental challenge, was higher (P < 0.05) in birds that did not receive the enzyme supplementation. During the period from 1 to 21 d of age, the live weight and weight gain were higher (P < 0.05) for birds that were not supplemented. From 1 to 42 d, supplementation with β-mannanase resulted in worst feed conversion. One week after the challenge, the birds that consumed control diets and that were challenged had higher (P < 0.05) proportion of activated T CD8 lymphocyte populations. Unchallenged birds supplemented with the enzyme exhibit higher proportions of CD4. At this same age, there was greater (P < 0.05) crypt depth, smaller (P < 0.05) villus: crypt proportion, and higher (P < 0.05) number of goblet cells in the intestinal mucosa of the challenged birds compared to the control. However, at the age of 42 d, the birds that received the enzyme supplementation showed a lower crypt depth (P < 0.05), which resulted in a better villus: crypt proportion. Although not improving the performance of birds, supplementation with β-mannanase contributed positively to the quality and intestinal health of the broilers.
|
|---|
