ABSTRACT This study evaluated the behavior of broiler chickens subjected to thermal stress during different periods of the day and age of birds. A total of 180 one-day-old male broiler chicks were allocated to three chambers. Each chamber contained five boxes, with 12 chicks/box. Birds were assigned to a completely randomized design. The birds were filmed, and the images recorded every minute during the two periods: morning (from 08:00 to 09:00 h) and afternoon (from 17:00 to 18:00 h), at […]

ABSTRACT In this study, we evaluated how guanidinoacetic acid (GAA) addition in diets with various metabolizable energy (ME) contents affects the performance of broiler chickens. We also estimated the equivalence of GAA in ME. We distributed 1,280 one-day-old broilers in a completely randomized design with eight treatments, eight replicates, and twenty birds per experimental unit. Treatments were based on ME levels (2,775-2,875-2,975 kcal/kg; 2,850-2,950-3,050 kcal/kg; 2,925-3,025-3,125 kcal/kg; or 3,000-3,100-3,200 kcal/kg, from 1 to 7, 8 to 21, and 22 to […]

ABSTRACT The objective of this study was to determine the energy value of pasta waste through a metabolism trial and determine the best level of its inclusion in broiler diets. In the metabolism trial, sixty 14-day-old birds were assigned to two treatments (control diet and a diet in which 30% was replaced by the byproduct) with six replicates and five birds per experimental unit. In the performance trial, 525 one-day-old chicks were assigned to treatments consisting of five levels of […]

ABSTRACT Precise body composition measurements are essential in animal nutrition studies because the impact of treatments is evaluated based on changes in body weight and composition. Various indirect techniques for animal compositional evaluation have been developed and evaluated for applicability in animal nutrition studies. A fast, accurate, minimally invasive method that requires little input is considered the ideal for providing information about the animal. Measurements obtained by dual-energy x-ray absorptiometry (DXA) are highly correlated with those obtained by chemical analysis […]

The experiment was conducted to determine the nutritional requirement of calcium and the best calcium:available phosphorus ratio for commercial layers at the post-laying peak. A total of 324 Hy-Line W-36 laying hens were utilized in the period from 42 to 58 weeks of age, distributed in a completely randomized design in a 3 × 3 factorial arrangement, composed of three levels of calcium (39, 42 and 45 g/kg) and three calcium:phosphorus ratios (12.12:1; 10.53:1; and 9.30:1), totaling nine treatments with […]

The objective of this study was to determine the ideal digestible tryptophan:digestible lysine ratio in diets for laying hens from 24 to 40 weeks of age. Two hundred and forty Hy-Line W-36 laying hens at 24 weeks of age were distributed in a completely randomized design, with five treatments, eight replicates and six birds per experimental unit. The digestible tryptophan levels in the experimental diets were 1.57; 1.68; 1.79; 1.90 and 2.01 g/kg, providing ratios of digestible tryptophan:digestible lysine of […]

An experiment with 630 one-day-old chicks experimentally inoculated with Salmonella Typhimurium was performed to evaluate the effects of an organic acid blend (benzoic, fumaric and 2-hydroxi-4-methylltio-butanoic – HMTBa) on intestinal health and performance. The experimental challenge with Salmonella Typhimurium occurred in two different routes of administration: via crop on the first day after hatching, and via feed, offered from seven to 14 days of age. These groups were treated with organic acids in a 3 × 2 (agent versus acid) […]

Objetivou-se com este estudo rastrear a inclusão de farinha de carne e ossos bovinos em dietas para poedeiras comerciais, por meio da análise dos ovos e de suas frações (gema e albúmen), pela técnica dos isótopos estáveis do carbono e nitrogênio e avaliar o índice analítico mínimo detectável. Foram utilizadas 240 galinhas poedeiras da linhagem Shaver White de 73 semanas de idade, distribuídas em delineamento inteiramente casualizado, com cinco tratamentos e seis repetições. Foram avaliados cinco níveis de inclusão (0; […]

Um experimento foi conduzido para verificar a influência da glutamina no turnover do carbono na mucosa intestinal de leitões desmamados. Nove matrizes receberam dietas compostas basicamente de plantas do ciclo fotossintético C4 durante toda a gestação (d‰13C = 17,12) e lactação (d‰13C = -19,26). Os leitões foram desmamados aos 21 dias de idade e 68 deles foram alimentados com ração composta de plantas do ciclo fotossintético C3 (d‰13C = -25,12). Os leitões foram aleatoriamente distribuídos em duas dietas: uma sem […]

O produto mais importante do conhecimento é a ignorância. A situação sugere a imagem de alguém que vive numa ilha de conhecimento cercado por um mar de ignorância. Quando a área dessa ilha aumenta pelo progresso da ciência, também aumenta o litoral, – a fronteira com o desconhecido. Esta expansão é o fruto mais valioso do conhecimento (David Gross, Nobel em Física, 2004). O uso dos isótopos estáveis dos bioelementos (CHON’S) presentes na Atmosfera, Hidrosfera, Litosfera e Biosfera enquadra-se neste […]