DESEMPENHO ZOOTÉCNICO DE JUVENIS DE TILÁPIAS DO NILO (Oreochromis niloticus) ALIMENTADOS COM CEPAS PROBIÓTICAS E SUBMETIDOS A DESAFIO SANITÁRIO

O surgimento de doenças ocasionadas pelo estresse durante o cultivo de juvenis vem tornando-se comum devido à intensificação dos sistemas de produção, ocorrendo elevada mortalidade e prejuízos econômicos ao produtor. Mediante esse contexto, os probióticos que são um conjunto de micro-organismos vivos, estão sendo utilizados devido à sua capacidade de estabelecer-se e multiplicar-se no intestino do hospedeiro e promover o equilíbrio da microbiota, contribuindo com a sanidade e o desempenho dos peixes principalmente nas primeiras semanas de vida. Objetivou-se avaliar o desempenho de juvenis de tilápias do Nilo alimentados com cepas probióticas e submetidos a desafio sanitário. Foram utilizados 180 juvenis, distribuídos em delineamento inteiramente casualizado, com três tratamentos, quatro repetições e 15 peixes como unidade experimental. Os tratamentos foram: T1 - peixes cultivados em água limpa sem o uso de probiótico; T2 - peixes cultivados em água sob desafio e sem o uso de probiótico e T3 - peixes cultivados em água sob desafio e com o uso de probiótico. Não houve efeito significativo (P>0,05) nos parâmetros de desempenho zootécnico, no consumo de ração e sobrevivência. A utilização de probiótico na ração não mostrou-se hábil para proporcionar melhorias no desempenho, consumo de ração e na sobrevivência de juvenis de tilápias do Nilo no período de 30 dias de cultivo. Palavras-chave: dejetos de suínos; ganho de peso; piscicultura; probiótico

Body composition and net and dietary macrominerals requirements of Nellore steers under grazing

This experiment was carried out with the objective of determining the macrominerals (Ca, P, Mg, K and Na) requirements of Nellore steers under grazing. Twenty four Nellore steers (371 ± 14 kg of BW and 26 mo old) were used. Four steers were slaughtered at the beginning of the experiment (reference group), serving as a reference in subsequent study. The remaining 20 animals were weighed and distributed into a completely randomized design with four supplementation levels offer: 0.0 (mineral mixture - control), 0.3, 0.6 and 0.9% of BW, with five replications. The supplements, based on ground corn, soybean meal and/or urea, were previously balanced to achieve an average daily gain of 350, 650 and 850g, respectively, for the different supplementation levels offer. The contents of macrominerals retained in the animal body were determined by regression equations of the macrominerals body content logarithm in function of the empty body weight logarithm (EBW). Net macrominerals requirements for a gain of 1kg of EBW were obtained using the equation Y'= b.10ª.Xb-1, with a and b, respectively, the intercept and the regression coefficient of the prediction equations of macrominerals in the animal body contents for each macromineral considered. The concentrations of all macrominerals, in the empty body weight and gain of the empty body weight, decreased with the increase in the body weight. Total calcium and phosphorus dietary requirements are higher than those recommended in the literature

Whole scrapings of cassava root in diets for broilers from 1 to 21 days of age

The study was conducted to evaluate the effect of including whole cassava root scrapings (WCS) in diets of broilers on performance and the metabolizability of dry matter, crude protein, and gross energy and on nitrogenous balance. Four hundred female and 100 male broilers from Ross strain were used in the performance and metabolism studies, respectively. In both studies, broilers were allotted in completely randomized block design with five treatments and four replicates. The experimental unit was represented for twenty birds per box for performance study and five birds per metabolic cage for metabolism study. The treatments consisted of diets containing 0, 5, 10, 15, and 20% WCS inclusion. Up to 5.1% WCS can be included in the diet of broilers from 1 to 21 without compromising feed conversion and productive efficiency index. Dry matter, crude protein, and gross energy metabolizability and the nitrogen balance of the diets are not influenced by the inclusion of whole cassava root scrapings up to 20% in diets of broilers from 1 to 21 days of age

Acta Scientiarum : Biological Sciences

Texto completo: acesso restrito. p. 139-144The experiment was conducted to evaluate losses and nutritive value of elephant grass silage containing increasing levels of cottonseed meal. The experimental design was completely randomized, with five treatments: 0, 7, 14, 21 and 28% inclusion of cottonseed meal, and four replications. The material was chopped and packed in PVC silos and stored for 80 days. The pH and dry matter (DM), crude protein, lignin and ether extract of the silages increased linearly with the addition of cottonseed meal, while the levels of acid detergent insoluble nitrogen, neutral detergent fiber, acid detergent fiber, cellulose and hemicellulose decreased linearly. The addition of 28% cottonseed meal reduced the in situ disappearance of DM (48h) to values lower than those of silage without additives. The concentration of ammonia nitrogen and the losses from gases and effluent were reduced. The inclusion of 28% cottonseed meal in elephant grass silage containing 18.4% DM improved the fermentation characteristics of silage more efficiently by reducing the moisture content and effluent losses, starting at the 7% level of inclusion

Semina: Ciências Agrárias

p. 2963-2976The objective of this study was to evaluate the correlation between intake and ingestive behavior of crossbred heifers in grazing tropical. The experiment was conducted on the Princesa do Mateiro Farm, in the city of Ribeirão do Largo, Bahia. A total of 20 heifers with genetic makeup 5/8 dairy Guzerá and 3/8 Holstein, average age of 18 months and body weight of 187 ± 13.1 kg have been used. The experiment lasted 224 days and involved animals raised in a rotational grazing system with Brachiaria brizantha cv. Marandú. Grazing time was not correlated with any of the variables associated with intake. Rumination time showed positive correlations with the intake of forage dry matter (DMIF) and neutral detergent fiber (NDFI). Variables associated with the time spent on feeding at the trough, overall feeding and total chewing were not correlated with intake (P>0.05). There have been positive correlations between the number of grazing periods (NGP) and rumination periods (NRP) and total DM intake (TDMI), organic matter (OMI), forage (DMIF), neutral detergent fiber (NDFI), total carbohydrates (TCHI) and ether extract (EEI). Crude protein intake (CPI) was positively correlated with NGP and NRP. The mouthful rate was positively correlated with TDMI, OMI, DMIF, NDFI, TCHI, EEI and CPI. Average time per swallow was negatively correlated with TDMI, OMI, NDFI, TCHI and EEI. Positive correlations have been observed between the number of mouthfuls per day and TDMI, OMI, DMIF, NDFI, TCHI, EEI. The number of chews per bolus showed negative correlations with DMIS and CPI. The time per cake ruminated has correlated negatively with the intake of crude protein. The number of chews per bolus showed positive correlations with the intakes of dry matter and neutral detergent fiber. The number of boli per day showed positive correlations with DMIF and TCHI. The time spent on chewing showed no significant correlation with intake. In conflict with the national and international literature, the grazing time was not correlated with intake by grass-fed crossbred heifers. The number of activities, the time spent on them and the mouthful rate where shown to be highly associated with the intake variables and can therefore arrange equations to predict intake through the analysis of feeding behavior. The number of mouthfuls performed each day contributes to the intake by pasture-grazed heifers

Multivariate analysis of productive and nutritional traits and feeding behavior of sheep fed roughage-free diets

ABSTRACT The objective of this study was to evaluate productive traits in sheep fed roughage-free diets by multivariate analysis. Forty lambs were used in this study: 20 Santa Inês animals, consisting of 10 uncastrated males and 10 females; and 20 crossbreds (½ Santa Inês × Dorper), consisting of 10 uncastrated males and 10 females, at an average age of five months. Lambs were randomly allocated into the following treatments: Santa Inês males fed once daily (SM1); Santa Inês males fed twice daily (SM2); Santa Inês females fed once daily (SF1); Santa Inês females fed twice daily (SF2); crossbred males fed once daily (CM1); crossbred males fed twice daily (CM2); crossbred females fed once daily (CF1); and crossbred females fed twice daily (CF2). In the multivariate analysis, a difference was detected between the mean values for production classes and feeding-behavior variables (Wilks, Pillai, Hotelling-Lawley, and Roy tests). Tocher's optimization method had two groups formed: Group I, comprising treatments SM1, SM2, SF1, SF2, CF1, and CF2; and Group II, containing treatments CM1 and CM2 (crossbred males). When production and cud chews per day were evaluated, neutral detergent fiber digestibility and final weight were the performance-digestibility variables that most contributed to explaining the variation between treatments. When the feeding behavior was assessed, the time spent on other activities was the variable that most contributed. The crossbred genotype (½ Santa Inês × Dorper) and the male sex have superior performance for weight-related traits. However, when these animals are confined with females, it is recommended to supply the feed only once daily, irrespective of the genetic group