Scielo RSS <![CDATA[Revista Brasileira de Zootecnia]]> vol. 44 num. 4 lang. en <![CDATA[SciELO Logo]]> <![CDATA[Length–weight relationship and prediction equations of body composition for growing-finishing cage-farmed Nile tilapia]]> The objective of the present study was to develop models for predicting live weight from the length-weight relationship and body composition of Nile tilapia. A total of 3,000 juvenile fish (initial weight = 28.6±4.16 g and standard length = 13.8±0.16 cm) were distributed into three circular cages (12 m3 each). The fish were hand-fed extruded diets containing 332 g kgâ€"1 of crude protein and 3,230 kcal kgâ€"1 of digestible energy, until apparent satiety, twice daily, for 100 days. Twelve fish were collected from each cage every 20 days for measurements of body weight and length, and proximate composition analysis; statistical analysis was conducted using linear regression. The value of the slope b and the intercept for the length-weight relationship were 3.0604 and 0.0203, respectively. The prediction equations obtained for body moisture (MO), crude protein (CP), crude lipid (CL), and ash against body weight (BW) in g/100 g of fish were as follows: MO = 70.0090 â€" 0.0071BW; CP = 13.7550 + 0.0037BW; CL = 9.2636 + 0.0057BW; and ash = 4.2392 â€" 0.0024BW. It is possible to develop equations to predict body weight and composition, which can be used to control the production of Nile tilapia and improve its commercial value. <![CDATA[Feeding behavior and responses in grazing lactating cows supplemented with peanut cake]]> This experiment was conducted to study the substitution of soybean meal with peanut cake in the supplement by assessing the feeding behavior and the interaction between the thermal environment and the physiological responses of eight crossbred cows with an average live weight of 500 kg. Cows were divided into two 4 × 4 Latin squares and managed on pasture. The peanut cake was included at the levels of 0, 330, 660, and 1,000 g kgâˆ'1 in the supplement as a replacement for soybean meal. The feeding behavior variables were not affected by the levels of peanut cake. No differences were found for the physiological parameters of the animals with the replacement of soybean meal for peanut cake in the supplements. Peanut cake can replace up to 100% soybean meal in the supplement of grazing lactating crossbred cows without altering the feeding behavior or physiological parameters of the animals. <![CDATA[Production, composition and processing of milk from ewes fed soybean seeds]]> The objective of this study was to evaluate production, chemical composition, and estimates of total solids and fatty acid profile of milk from 1/2 Lacaune × 1/2 Ile de France ewes fed control and soybean seeds-supplemented diets. Additionally, Roquefort type cheese was also produced and subjected to sensory analysis. Twenty four 1/2 Lacaune × 1/2 Ile de France ewes were divided into three groups and fed a control diet and diets containing 70 and 140 g kgâˆ'1 soybean as fed, during the lactation period. The remainder milk was used to produce Roquefort cheese. The experimental design was completely randomized, with three treatments (0, 70, and 140 g of soybean kgâˆ'1 as fed) and eight repetitions. The diets did not affect significantly the performance (56.72 kg post-birth weight; 62.63 kg weight after 56 lactation days; 2.03 kg dayâˆ'1 dry matter intake; 0.11 kg average daily weight gain), or milk production (443.61 mL dayâˆ'1), density (1.035 g mLâ€"1), acidity (19.33 °D), and pH (6.41) of lactating ewes. Milk chemical composition was (per 100 g of milk): 14.86 g total solids, 9.84 g solids not fat, 4.98 g protein, 4.14 g casein, 5.03 g fat, and 4.11 g lactose. Saturated (72.07 g/100 g of fat), monounsaturated (21.48 g/100 g of fat) and polyunsaturated (6.37 g/100 g of fat) fatty acids were not significantly different. However, the polyunsaturated linoleic acid was significantly different in the milk from ewes fed the diet containing 140 g of soybean kgâˆ'1 as fed (5.58 g/100 g of fat) compared with those fed the control diet and 70 g of soybean kgâˆ'1 as fed (3.82 g/100 g of fat). The Roquefort type cheese had excellent acceptance by the panel. The highest cheese yield was obtained with the milk from ewes fed diets containing 70 g kgâ€"1 soybean as fed. A diet containing 140 g kgâˆ'1 soybean as fed is recommended as it leads to greater linoleic acid content in the ewes milk, improving the lipid fractions and nutritional quality of the milk. <![CDATA[A note on the distribution of genetic diversity of Anglo-Nubian goats in central-northern farms of PiauĂ­, Brazil]]> The objective of this study was to characterize the genetic variability of Anglo-Nubian goats using microsatellite markers. The study was conducted using herds from four municipalities of Central-Northern Piauí (Teresina, José de Freitas, Campo Maior, and Angical), where technical information is scarce. Seven markers suggested by FAO were used (ILSTS11, McM527, INRA23, ETH10, OarfCB304, OarfCB48, and MAF209). The samples were genotyped using a 7% polyacrylamide gel. The average number of alleles per locus was 4.0, with observed and expected heterozygosity of 0.38 and 0.55, respectively. Few deviations from the Hardy-Weinberg equilibrium were observed for each population. Only two loci deviated significantly in two localities. The coefficient of gene differentiation (GSTâ€(tm)) indicated that 11.9% of the genetic variation was distributed among populations, and according to the coefficient of inbreeding (GIS = 0.23 and FIS = 0.23), there is a deficiency of heterozygotes within populations. These findings corroborate the Bayesian analyses performed with the STRUCTURE software, which revealed three distinct and moderately structured groups. The graphic analysis showed that Teresina and José de Freitas are isolated groups, while Angical and Campo Maior share most of their alleles. Despite this, the level of diversity among herds was low. Based on this genetic structure, exchange of reproducers among municipalities is recommended for the maintenance of the breed. <![CDATA[Maternal age influences on reproductive rates in Nile tilapia (Oreochromis niloticus)]]> In this study we examined the effects of the maternal age on the fecundity (absolute and relative), egg production, and fertilization rates of Nile tilapia (Oreochromis niloticus). Females were divided into three groups: Group 1 (6 years old), Group 2 (3 years old), and Group 3 (8 months old). Males of eight months were used in all groups. Twice a week, the femalesâ€(tm) mouths were examined, and if they had eggs, these were removed and transferred to 2-L incubators. No difference was observed in the absolute fecundity between the different maternal age groups. Relative fecundity and egg production was greater in Group 3 (8 months) and fertilization rates were lower in Group 1 (6 years). Younger tilapias are more viable for egg production, because they have better reproductive indexes.