ABSTRACT. Macrobrachium amazonicum is a species of freshwater shrimp of great importance for aquaculture and to know its reproductive potential, through the study of its fertility is necessary. Therefore, this study aimed to evaluate the effect of two different diets on the reproductive performance of the species, whether or not adopting the ablation procedure. The experiment was carried out in a completely randomized design in a 2 x 2 factorial arrangement, with two types of feed (inert and fresh) and two conditions (ablated and non-ablated females), using six replicates per treatment. After 10 days of spawning, the eggs were removed and counted in their entirety. For each female, three spawns were obtained, totaling 72 samples. The fertility rate, the interval between spawning and the weight gain of the females were analyzed. There was no interaction between the studied factors, except for weight gain, in which ablated females that received fresh feed gained up to three times more weight than non-ablated females. Females that received fresh feed obtained higher fertility (1,373.9 eggs) than those that received only inert feed (1,084.1 eggs). The interval between spawns was 1.6 days shorter in ablated females.

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 Two experiments were conducted using direct method to determine the standardized ileal phosphorus (P) digestibility coefficient (SIPDC) of meat and bone meal (MBM) and poultry byproduct meal (PBM) for broilers. In the first experiment, three MBM from different batches were evaluated, with four treatments (MBMI, MBMII, MBMIII, and a P-free diet) and nine replicates of seven birds each, totaling 252 birds distributed across a completely randomized design. The P-free diet was used to determine endogenous P losses. Titanium dioxide (5 g kg−1) was used as an indigestible indicator. In the second experiment, three PBM from different batches were evaluated, with 189 birds distributed over three treatments (PBMI, PBMII, and PBMIII) and nine replicates of seven birds each. These two experiments were conducted when birds were 19-22 days old. The birds were euthanized to collect the ileal content. Using the P-free diet, endogenous P losses were determined at 94.9 mg kg−1 dry matter intake. Standardized ileal P digestibility of MBMI (0.65) and MBMIII (0.69) was higher compared with MBMII (0.49). The SIPDC determined for three PBM sources were similar and 0.96, 0.96, and 0.93 for PBMI, PBMII, and PBMIII, respectively. The present study demonstrates that P in MBM is not as available as it is believed and that the variability between batches should be considered by nutritionists, while PBM can be considered an excellent P source to broiler diets.

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.

RESUMO. Foi realizado um experimento com frangos de corte fêmeas, objetivando-se avaliar o efeito da utilização de probióticos e simbióticos sobre o desempenho e rendimento de carcaça e dos principais cortes comerciais e vísceras comestíveis destes animais. Foram utilizados 720 pintos de um dia de idade da linhagem Cobb, distribuídos em um delineamento experimental inteiramente casualizado, com quatro tratamentos e seis repetições de 30 aves cada em uma densidade de 10 aves/metro quadrado (m2). Aos 42 dias de idade foram abatidos dois frangos por repetição, para a avaliação do rendimento de carcaça e suas partes. A inclusão de probióticos e simbióticos na ração não proporcionou diferença significativa no rendimento de carcaça e suas partes sendo equivalente ao tratamento com antibióticos. Não foi observada diferença significativa entre os tratamentos, inclusive nos controles que não receberam qualquer fator aditivo. Da mesma forma os demais parâmetros de desempenho foram equivalentes para os quatro tratamentos, com exceção do ganho de peso, que foi significativamente menor no tratamento probiótico. Conclui-se que esses aditivos são uma alternativa importante na substituição dos antibióticos como melhoradores de crescimento, os quais já foram banidos em muitos países.

ABSTRACT. An experiment was carried out with female broilers, aiming to evaluate the effect of using probiotics and symbiotics on growth performance and yield of carcasses and of the main commercial cuts and edible viscera. A total of 720 one-day-old Cobb chicks, distributed in a completely randomized experimental design with four treatments and six replicates of 30 birds each at a stocking density of 10 birds per square meter (m2). At 42 days old two broilers of each experimental unit were sacrificed to evaluate the carcass yield and its parts. The carcass yield was not affected by the inclusion of probiotics and symbiotics in the diet being equivalent to the antibiotic group. No significant difference was observed among the treatments, even in the controls that did not receive any additive factor. All the performance parameters were similar for the four treatments, with the exception of weight gain, that was significantly lower in probiotic treatment. It was concluded that these additives are important alternative to replace antibiotics as growth enhancers, which have already been banned in many countries.

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.