ABSTRACT. The present study was carried out with the objective of determining the requirements for digestible lysine in Nile tilapia during the 500 to 600 g live weight stage. Isocaloric and isonitrogenous diets were tested with increasing amounts of digestible lysine. L-lysine HCl (78%) were used to replace glutamic acid at increasing levels, resulting in treatments of 9.3, 12.3, 15.3, 18.3 and 21.3 g kg-1 of digestible lysine. Three hundred Nile tilapias with an average weight of 519 ± 27.23 g were used and distributed among 25 tanks. The physical and chemical parameters of the water were pH, dissolved oxygen, salinity, conductivity and temperature. The mortality rate was registered daily. Two slaughters were performed at 28 and 50 days after the beginning of the experiment. It was estimated that an amount of 13.1 g kg-1 of digestible lysine was ideal for obtaining higher WG. Fish slaughtered after 50 days, the digestible lysine requirements were determined to be 14.5 g kg-1 for the lowest carcass humidity and 14.6 g kg-1 for the greatest carcass ethereal extract. Nile tilapias with live weight between 500 and 600 grams require 13.1 g kg-1 of digestible lysine in the diet for greater WG (90.53 g) and better FCR (2.55).

ABSTRACT. The aim of the present study was to evaluate the relationship between the level of fiber and its action period in diets to laying hens on performance and egg quality. 180 Hisex white hens (65 weeks-old) were randomly allocated to 3 groups of 60 birds each, comprising 10 replicates of six birds per treatment. The experimental design was factorial scheme considering three levels of fiber (2.50, 4.87 and 7.24%) in birds’ diets, and three action periods of this fiber (short - 21 days, medium - 56 days, and long - 105 days) in the feed. The estimates of treatments were firstly subjected to ANOVA and a subsequent Tukey test at 5%. Birds fed diets with moderate levels of fiber (4.87%) presented better (p < 0.05) performance. High levels of fiber caused a significant reduction in performance. Birds fed diets with low and moderate levels of fiber produced eggs with better (p < 0.05) quality. High levels of fiber caused a significant reduction in egg quality. The exposure of birds to diets with fiber for long-term caused a negative effect (p < 0.05) on performance, egg weight and percentage of its main structures, albumen height, yolk height, eggshell thickness, and the specific gravity.

ABSTRACT The objective of the present study was to evaluate the effects of xylanase and probiotic supplementation on the performance, carcass characteristics, intestinal pH, intestinal viscosity, and ileal microbiota of broiler chickens fed diets containing wheat bran. The study animals were kept in metal cages, and the study was performed using a completely randomized design, with four treatments, six birds per treatment, and six replicates. The four treatments included a control group, a probiotic-supplemented group, a xylanase-supplemented group, and a group that received both xylanase and probiotic supplementation. The diets of all four groups contained wheat bran (50 and 30 g/kg for the starter and grower phases, respectively) and phytase, and at 10 d after hatching, the experimental birds were challenged orally with Eimeria sp commercial vaccine. During the initial phase, supplementation with xylanase, probiotics, or their combination yielded greater weight gains than the control diet; however, considering the period from 10-35 d, the chickens receiving xylanase + probiotic and the diet without the additives showed lower weight gain (2.746 and 2.600 kg, respectively). All the supplemented diets reduced cecum viscosity, and supplementation with probiotic showed a significantly lower pH (6.11). The ileal microbiota was also influenced by xylanase and probiotic supplementation, modulating the frequencies of the genera Lactobacillus and Clostridium. The positive effects of supplementation with xylanase or probiotics alone were similar to those of co-supplementation, and no associative effect was observed.

ABSTRACT. This study aimed to evaluate açaí meal in diets for commercial laying hens on apparent nutrient digestibility and apparent metabolizable energy. A total of 72 Hissex White laying hens (52-wks-old) were distributed in a completely randomized design, where treatments consisted of a control diet and an experimental diet (25% açaí meal) with six replicates of six birds each. Data collected were subjected to polynomial regression at 5%. Differences (p < 0.05) were detected in digestibility of all evaluated nutrients. Hens fed diets with 25% açaí meal presented worse (p < 0.05) metabolization and use of energy content. It can be concluded that hens fed diets containing açaí meal presented better use of crude protein, non-fiber carbohydrates and mineral matter. However, there was worse use of dry matter, fiber carbohydrates and ether extract. This result directly affected the energy metabolism of the birds. The inclusion of açaí meal reduced the energy use.

ABSTRACT Five experiments were conducted to estimate the digestible threonine requirements of slow-growing broilers: experiment 1, starter phase (days 10 to 28); experiment 2, grower I phase (days 29 to 49); experiment 3, grower II phase (days 50 to 69); experiment 4, finisher phase (days 70 to 84); and experiment 5, which was specifically conducted to determine the production of intestinal mucin over two periods (days 50 to 69 and 70 to 84). Different birds were used in all experiments. A completely randomized design with five treatments and four replicates was used. Treatments consisted of increasing the values of digestible threonine in the diet through basal feed supplementation with L-threonine (98.5%), which was added instead of cornstarch. The following values of digestible threonine were investigated: 0.622, 0.697, 0.772, 0.847, and 0.922% in experiment 1; 0.586, 0.662, 0.738, 0.814, and 0.890% in experiment 2; 0.570, 0.640, 0.71, 0.780, and 0.850% in experiments 3 and 5; and 0.520, 0.595, 0.670, 0.745, and 0.820% in experiments 4 and 5. The digestible threonine values presented quadratic effects on feed conversion ratio in experiments 1, 2, and 3. Digestible threonine values of 0.628 and 0.609% resulted in higher villus height and greater duodenal crypt depth, respectively. Digestible threonine values of 0.762, 0.767, and 0.733% may be recommended for the starter, grower I, and grower II phases, respectively, based on the best feed conversion ratio. In addition, a digestible threonine level of 0.694% may be recommended for the finisher phase based on the highest production of intestinal mucin.

RESUMO A determinação da real exigência de lisina é fundamental, por ser um aminoácido essencial e desempenhar importantes funções no metabolismo dos frangos de corte. Além disto, apresenta-se como segundo aminoácido limitante para frangos de corte alimentados com rações formuladas a base de milho e farelo de soja. O objetivo deste estudo foi determinar a exigência de lisina digestível para frangos de corte machos de menor potencial genético para crescimento em sistema semiconfinado, bem como avaliar os efeitos de diferentes valores de lisina digestível sobre o desempenho e características de carcaça. Foram utilizados 300 frangos de corte, da linhagem comercial EMBRAPA 041, com pesoinicial médio de 987 g. Os frangos foram distribuídos em 20 unidades experimentais em um delineamento inteiramente casualizado, com cinco tratamentos (0,586; 0,746; 0,906; 1,066 e 1,226% de lisina digestível), quatro repetições e quinze frangos por unidade experimental. Nos dois períodos avaliados, verificaram-se efeito linear dos níveis de lisina digestível sobre a ingestão e eficiência na utilização de lisina, e efeito quadrático sobre peso vivo final, ganho de peso e a conversão alimentar. Verificou-se efeito quadrático sobre os pesos absolutos da carcaça, peito, coxa+sobrecoxa e rendimento da moela. Podem ser recomendadas, respectivamente, para máximo ganho de peso rações com 1,040% e 1,103% de lisina digestível nos períodos de 35 aos 70 e 35 aos 84 dias de idade.

ABSTRACT Determining the actual lysine requirement is crucial as it is an essential amino acid and plays animportant role in the metabolism of broilers. In addition, it is the second limiting amino acid for broilers fed with rations formulated basedon corn and soybean meal. The aim of this study was to determine the digestible lysine requirement for male broilers with lower genetic potential for growth in a semi-confined system as well as to evaluate the effects of different values of digestible lysine on performance and carcass characteristics. A total of 300 broiler chickensfrom a commercial lineage EMBRAPA 041 were used with an average initial weight of 987 g. The broilers were distributed into 20 experimental units in a completely randomized design with five treatments (0.586; 0.746; 0.906; 1.066, and 1.226% digestible lysine), four replicates and 15 broilers per experimental unit.In both periods, there were linear effect of digestible lysine values on the lysine intake and lysine utilization efficiency and quadratic effect on final body weight, weight gain and feed: gain ratio.There was a quadratic effect on the absolute weight of carcasses, breast, thigh + drumstick and income gizzard.For rearing of male broilers with lesser genetic growth potential reared in semi-confinement, rations with 1.040% and 1.103% digestible lysine can be recommended for maximum weight gain in periods from 35 to 70 and 35 to 84 days of age, respectively.

O objetivo deste trabalho foi estudar diferentes métodos reprodutivos em aves de duas linhagens semipesadas e avaliar seus efeitos sobre os processos de incubação artificial dos ovos e do rendimento de carcaça dos pintainhos. O delineamento experimental foi inteiramente casualisado em esquema fatorial (2 x 2) com os fatores: métodos reprodutivos (inseminação artificial e monta natural) e duas linhagens semipesadas (Plymouth Rock Barrada e Rhode Island Red). Foram utilizadas 26 matrizes (23 fêmeas e 3 machos) para cada fator que originaram 62 ovos cada, totalizando 248 ovos, sendo cada ovo uma repetição. Os ovos foram pesados antes e após o período de incubação para determinação da perda de peso e realização de análise comparativa entre o peso do ovo e o peso do pinto. Durante o período de incubação foi avaliado o desempenho reprodutivo das matrizes, e após o nascimento, foram abatidos 8 pintos de cada fator para análise do rendimento de carcaça dos mesmos. Não foram encontradas diferenças significativas (P>0,05) entre o desempenho reprodutivo e a relação entre o peso do pinto e o peso do ovo. O peso do saco vitelino e peso do fígado foram afetados (P<0,05) pelos tratamentos tendo a linhagem Plymouth Rock Barrada apresentado melhores resultados.

The objective of this study was different reproductive methods in birds from two semi-heavy lineages and evaluate their effects on the processes of artificial incubation of eggs and carcass yield of chicks. The experimental design was completely randomized factorial (2 x 2) with factors: reproductive methods (artificial insemination and natural breeding) and two semi-heavy lineages (Plymouth Barred Rock and Rhode Island Red). Were used 26 matrices (23 females and 3 males) for each factor that led to 62 eggs each, totaling 248 eggs, each egg being a repeat. The eggs were weighed before and after the incubation period to determine weight loss and performing comparative analysis between the egg weight and the weight of chick. During the incubation period was evaluated the reproductive performance of the matrices, and after birth, 8 chicks each factor were killed for analysis of carcass thereof. No significant differences (P> 0.05) were found between reproductive performance and the relationship between chick weight and egg weight. The yolk sac and liver weights were affected (P <0.05) by treatment with a Plymouth Rock Barred strain showed the best results.