# Coccidia Vaccine Challenge and Exogenous Enzyme Supplementation in Broiler Chicken 2—Effect on Apparent Ileal Nutrient and Energy Digestibility and Intestinal Morphology 7 and 14 Days Post-Challenge

## TL;DR

This study shows how coccidia vaccines and enzyme supplements affect broiler chickens' digestion and growth, with diet type influencing recovery.

## Contribution

The study reveals that diet type influences recovery from coccidia challenge and enzyme supplementation improves performance in broiler chickens.

## Key findings

- Coccidia challenge reduced weight gain and feed efficiency in broilers on corn-soybean diets but improved recovery on wheat-corn diets.
- Exogenous enzyme supplementation increased weight gain in challenged broilers, especially on corn-soybean diets.
- Coccidia challenge altered intestinal morphology, with enzyme effects observed in wheat-corn-fed birds.

## Abstract

The efficiency with which the nutrients and energy in any diet are digested, absorbed, and utilized depends on several factors, with the health status of the bird’s gastrointestinal tract playing an important role. The protozoan parasite Eimeria has been reported to significantly reduce the performance of birds because of poor absorption of nutrients in the small intestine. In this study, the effect of Eimeria sp. challenge and exogenous enzyme supplementation on performance and nutrient digestibility in broilers fed corn-soybean meal- or wheat-corn–SBM-based diets was examined. During the first 7 days post-challenge (days 14–21), in birds fed the corn–soybean-meal-based diets, the coccidia vaccine challenge (CVC) resulted in lower BWG and feed efficiency, while birds on the enzyme-supplemented diets had higher BWG compared to birds on diets without enzyme supplementation. However, the CVC birds fed the wheat–corn–soybean-meal-based diets performed better (BWG and feed efficiency) compared to the unchallenged birds during the recovery phase (days 21–28). Findings from this study showed that the effect of CVC on broiler chickens’ performance during the recovery phase may be influenced by diet type.

The effect of exogenous mixed-enzyme supplementation (xylanase, β-glucanase, and pectinase) and coccidia vaccine challenge (CVC, Coccivac B-52™) on broilers fed a corn–SBM (CS) and a wheat–CS (WCS)-based diet was examined in this study. On day 14, 448 Cobb by-product breeder male broiler chickens were assigned to treatments (factorial arrangement) in a completely randomized design, with each treatment replicated seven times. Treatment effect was evaluated within each diet type as a 2 (enzyme levels) x 2 (CVC, 0 or 20X) factorial arrangement of treatments 7 and 14 days post-CVC. The 7-day (days 14–21) post-CVC, BWG, and feed efficiency (birds on the CS-based diet) were lower (p < 0.05), while birds on enzyme-supplemented diets had higher (p < 0.05) BWG compared to birds on diets without enzyme supplementation. Between days 21 and 28, an interaction between CVC and exogenous enzyme resulted in higher (p < 0.05) BWG compared with the challenged birds fed diets without enzyme supplementation. For birds fed WCS-based diets, CVC influenced (p < 0.05) BWG and feed efficiency (decreased days 14–21 and increased days 21–28), while CVC birds had higher BWG and feed efficiency 14 days post-CVC. Apparent ileal digestibility of dry matter, energy, and DE were lower (p < 0.05) in CVC broilers fed either the CS- or WCS-based diets (7 and 14 days post-CVC). Interaction between CVC and exogenous enzyme supplementation indicated that CVC, irrespective of exogenous enzyme supplementation with the WCS-based diet, decreased (p < 0.05) Ca utilization (7 days post-CVC) but increased (p < 0.05) Ca utilization compared to CVC birds without enzyme supplementation 14 days post-challenge. Seven days post-CVC, irrespective of the diet type, CVC resulted in lower (p < 0.05) duodenal VH and VH:CD and higher (p < 0.05) CD. Enzyme supplementation influenced (p < 0.05) duodenal CD (increased) and VH:CD (decreased) in birds fed the WCS-based diet. Results from this study showed that complete recovery from CVC was influenced by diet type, with CVC birds fed WCS-based diet having higher BWG and feed efficiency compared to the unchallenged birds.