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. This study aimed to investigate direct and indirect correlations of methodologies of bone quality analysis from brown egg layers, at final of the production cycle. Twelve femurs of Dekalb Brown laying hens, euthanized at 85-week-old, were assessed to evaluate breaking strength (BS), Seedor index (SI), mineral matter (MM), calcium (Ca) and phosphorus (P) contents, besides cortical (CorD), medullar (MedD) and epiphysis (EpiD) diameters. Correlations and path analysis were obtained with the aid of SAS® University (p ≤ 0.05). The BS directly represented the bone quality and was compared to other methodologies. Greater linear correlations occurred between BS and MM (r = 0.82), MM and Ca (r = 0.72), and BS and Ca (r = 0.70). The MM content displayed the greatest direct effect on the BS (r = 0.53). The Ca content showed a reduced direct effect on the BS (r = 0.18), with indirect effects through MM content (r = 0.44) and EpiD (r = 0.15), however, presented a great total correlation (r = 0.78). Determination of mineral matter content is the main methodology associated with femur breaking strength from brown egg layers at final of the productive cycle. Because of that, this methodology is more reliable to determine bone quality.

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.

RESUMO: O objetivo deste trabalho foi investigar a inclusão de níveis de caulim na dieta de poedeiras semipesadas ao final do ciclo de produção. Foram utilizadas 288 galinhas semipesadas distribuídas em delineamento inteiramente casualizado com seis tratamentos de oito repetições, contendo seis aves por repetição. Quando as aves atingiram a idade de 63 semanas, foi iniciada a alimentação com as dietas experimentais. As dietas diferiam entre si pela inclusão de níveis crescentes de caulim: controle (sem aditivo); e a inclusão de 1, 2, 3, 4 e 5% de caulim na dieta. Foram avaliados o desempenho, a qualidade dos ovos, a morfologia intestinal e a umidade das excretas. A inclusão de caulim promoveu melhora na altura das vilosidades do jejuno, possibilitando menor consumo de ração. Não houve diferenças significativas para a qualidade dos ovos. A umidade das excretas diminuiu com o aumento do nível de caulim na dieta, respondendo de forma linear. A inclusão de caulim ao nível de 5% nas rações de poedeiras semipesadas ao final do ciclo de produção melhorou a morfometria intestinal e a qualidade dos excrementos por meio da redução de sua umidade.

ABSTRACT: This study investigated the inclusion of kaolin levels in the diet of brown egg layers at the end of the production cycle. A completely randomized design involved the distribution of 288 brown egg layers into six treatments of eight replications, with six birds per replication. When the birds reached the age of 63 weeks, the feeding of the experimental diets began. Diets differed by the inclusion of increasing levels of kaolin: Control (no additive), and the inclusion of 1%, 2%, 3%, 4%, and 5% kaolin. The performance, egg quality, intestinal morphometry, and excreta moisture were evaluated. The inclusion of kaolin promoted improvement in the jejunum villus height, enabling less feed intake; however, there were no significant differences in egg quality. The excreta moisture decreased linearly as the kaolin level in the diet increased. The inclusion of 5% kaolin in the diet of brown egg layers at the end of the production cycle improved intestinal morphometry and the quality of excreta through a reduction of moisture.

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 O objetivo nesta pesquisa foi determinar a composição bromatológica e os valores de energia metabolizável para frangos de corte de crescimento lento em diferentes idades dos ingredientes: farelo de algodão, farelo de arroz e farelo de trigo. Para determinação dos valores energéticos foi utilizado o método de coleta total de excretas em dois ensaios de digestibilidade de 15 a 25 e de 35 a 45 dias de idade. As aves foram distribuídas em delineamento inteiramente casualizado, avaliando o efeito da idade, com seis repetições constituídas de 10 aves, para cada ingrediente. Os valores de energia metabolizável aparente corrigida pelo balanço de nitrogênio (kcal/kg), para primeira e segunda idade respectivamente, foram: farelo de algodão, 1.255 e 1.564; farelo de arroz, 3.124 e 3.301; farelo de trigo, 2.211 e 2.383. Os alimentos apresentaram variação quanto a composição química, bem como o valor energético foi superior (P<0,05) para os frangos de maior idade.

Abstract The aim of this study was to evaluate bromatological composition and metabolizable energy values of cottonseed meal, rice meal, and wheat bran when provided to slow growth rate broilers at different ages. Energy values of 15- to 25- and 35- to 45-day-old broilers were determined by the total feces collection method using two digestibility bioassays. The birds were distributed in a completely randomized experimental design to evaluate the age effect, with six replicates of 10 chickens each, for each ingredient. Values of apparent metabolizable energy adjusted by nitrogen balance (kcal/kg), for the first and second ages were: 1,255 and 1,564 for cottonseed meal, 3,124 and 3,301 for rice meal, and, 2,211 and 2,383 for wheat bran, respectively. The ingredients showed some variations regarding chemical composition and energy values, which were higher (P < 0.05) in older broiler chickens.

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.

ABSTRACT Two experiments were conducted to evaluate the apparent metabolizable energy (AME), nitrogen-corrected apparent metabolizable energy (AMEn), and standardized ileal amino acid digestibility coefficient (SIDC) of extruded soybean cake (ESC) at four different extrusion temperatures: 90, 100, 110, and 120 °C. In experiment 1, 300 male broilers were randomly distributed into four treatments (600 g kg−1 reference diet + 400 g kg−1 of SBC at different extrusion temperatures) + reference diet, with six replicates of 10 birds. A metabolic assay using the total excreta collection method was performed from 14 to 23 days to determine AME and AMEn. Quadractic effect of the extrusion temperature was observed, with the maximum AMEn value estimated as 3424.99 kcal kg−1 for 105.58 °C. In experiment 2, 300 male broilers were randomly distributed into four treatments (453 g kg−1 protein free diet + 547 g kg−1 SBC at different extrusion temperatures) + protein free diet, with six replicates of 10 birds. Experimental diets were offered from 16 to 21 days, and at 21days, birds were sacrificed by cervical dislocation for collection of the ileal digesta to determine the SIDC of ESC. The best SIDC values for lysine (0.824%), methionine (0.908%), and cysteine (0.741%) were estimated at 117.72, 114.40, and 107.37 °C, respectively. The other amino acids evaluated showed a linear response, with better SIDC values with increasing extrusion temperatures. The extrusion temperatures affect metabolizable energy and amino acid digestibility of soybean cake for broilers, being important the standardization of extrusion temperature to maximize the nutritional value of soybean cake used in broiler diets.