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| Author(s): |
Lívia Carrasco Dornelas
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Botucatu. 2017-08-29. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária e Zootecnia. Botucatu |
| Defense date: | 2017-07-28 |
| Advisor: | José Roberto Sartori |
| Abstract | |
The objective of the current study was to evaluate the effects of protease supplementation on diet digestibility and growth performance of broilers raised under thermoneutral condition and cyclic heat stress. In a 2x2x2 factorial system [thermoneutral condition or heat stress vs. diets formulated to meet nutritional (positive control, PC) or diets with crude protein and amino acids below requirements by 6% (negative control, NC) x Protease: 0.200ppm], 320 one-day-old male Cobb broilers were distributed in 8 replicates. From 1 to 7 days of age, feed conversion ratio (FCR) was better in thermoneutral condition, and in heat stress, feed conversion ratio (FCR) was better when consume PC. Broilers in thermoneutral environment presented best FCR and greater weight gain during the period from 1 to 14 days. Increased feed consumption and weight gain were observed in broilers kept in thermoneutral environment in periods of 1 to 21 days and 1 to 35 days old. During the period from 1 to 35 days of age there was interaction between diet and protease, and broilers that were given diets CP presented best FCR when they received protease. Broilers receiving protease improved feed conversion when consumed PC compared to those receiving NC. Protease supplementation favored nitrogen balance, metabolizable crude protein, dry matter, apparent metabolizable energy and nitrogen-corrected apparent metabolizable energy in broiler chickens in heat stress with positive control diet. In conclusion, heat stress impairs the performance of broiler chickens and diets with crude protein and amino acids below requirements (NC) impairs feed conversion. Protease supplementation (200ppm) in diets with protein and amino acids (PC) improves the feed conversion of broiler chickens from 1 to 35 days of age. Protease supplementation (200ppm) improves the apparent metabolizable energy and nitrogencorrected apparent metabolizable energy in diets with reduced levels of protein and amino acids (NC) for broilers in thermoneutral temperature, as well as improving the metabolizability of crude protein, dry matter and energy in diets with recommended levels of protein and amino acids (PC) in heat stress. (AU) | |
| FAPESP's process: | 15/15263-2 - Effects of environmental temperature and diet supplementation with protease on growth performance and nutrient utilization by broilers |
| Grantee: | Livia Carrasco Dornelas |
| Support Opportunities: | Scholarships in Brazil - Master |