Influência do momento da inseminação na taxa de concepção e razão sexual de fêmeas zebuínas/Influence of the moment of insemination in the conception and sexual ratio in zebu females

Este trabalho foi realizado com objetivo de avaliar se o intervalo entre a inseminação e ovulação pode influenciar a taxa de prenhez e a razão sexual secundária da prole de fêmeas zebuínas submetidas à inseminação artificial em tempo fixo (IATF). Foram sincronizados 469 fêmeas, entre novilhas e vacas, alocadas aleatoriamente em três grupos experimentais: IA42, IA54 e IA66, inseminadas respectivamente às 42, 54 e 66 horas após a remoção do implante de progesterona. As taxas de concepção diferiram entre as categorias (p < 0,05), mas não entre os tratamentos resultando em 28% e 45% no grupo IA42, 34% e 47% no IA54 e finalmente 33% e 48% no IA66 para novilhas e vacas respectivamente. Os resultados demonstraram que o momento da inseminação não alterou a taxa de concepção nem a razão sexual secundária das crias, o que permite maleabilidade no momento de inseminação após sincronização e a busca por alternativas para manipular a razão sexual

Dynamics of Growth in Purebred Pacu (<i>Piaractus mesopotamicus</i>) and Tambaqui (<i>Colossoma macropomum</i>), and Their Reciprocal Hybrids, under Varied Feeding Programs: Insights from Nonlinear Models

We evaluated the growth performance of pacu and tambaqui and their reciprocal hybrids (tambacu and paqui) under different feeding programs. We raised 30 individuals from each species and their respective crosses, distributing them into three replicate cages with 10 individuals each. Throughout the 5-month experimental period, the fish were weighed six times while exposed to diverse feeding regimens involving three commercial diets with varying combinations of crude protein (CP) levels: 24%, 28%, and 32%. Growth curves were adjusted using nonlinear models. The evaluation period was insufficient for adjusting the logistic model for the tambaqui and paqui treatments with the highest initial protein intake. Pure pacu had a higher (p p < 0.05) final weight (A = 1137.12) than in the pacu (A = 889.12). Among the feeding programs, animals that received less CP showed greater growth potential; however, longer evaluation is important to verify if the initial CP intake has no significant positive effect on fish growth

Reproductive performance of female Nile tilapia ( Oreochromis niloticus ) fed diets with different digestible energy levels

ABSTRACT This study aimed to evaluate the reproductive performance of female Nile tilapia (Oreochromis niloticus) fed diets containing different levels of digestible energy (DE). The fish were housed in 15 fiberglass tanks (500 L) in a recirculating system at an average temperature of 27.5 °C. The treatments consisted of five diets with increasing levels of DE (3,200; 3,400; 3,600; 3,800; and 4,000 kcal/kg). The levels of DE did not significantly influence the final weight or the hepatosomatic, gonadosomatic, and visceral fat indices. The absolute fecundity was influenced by the treatments, for which the highest values were observed from the 3,600 kcal/kg DE level and upward. The proximate composition of the fish also had a significant effect on the variables crude protein, ether extract, and ash; the fish fed diets with higher levels of DE exhibited the lowest body protein content, while the accumulation of ether extract exhibited the opposite response. A level of 3,600 kcal/kg of digestible energy should be used in diets with 380 g/kg crude protein and a starch/lipid ratio of 1.33 for female Nile tilapia

Métodos alternativos de restrição alimentar na muda forçada de poedeiras comerciais Alternative methods of feed restriction in the forced molt of laying hens

Foram avaliados métodos alternativos de restrição alimentar qualitativa em comparação à técnica convencional de muda forçada. Utilizaram-se 480 galinhas Babcock de 78 semanas distribuídas em três níveis de restrição alimentar (100, 75 e 50%) e três percentuais de redução de peso corporal (15, 20 e 25%), cada um com cinco repetições de 32 aves. Quando as aves atingiram o percentual de redução de peso corporal, determinaram-se o volume globular, os percentuais de ovário, oviduto, moela, intestino e gordura abdominal e o comprimento de oviduto. A partir do 28º dia e durante cinco períodos de 28 dias, observaram-se as características quantitativas e qualitativas de produção pós-muda. O maior período de restrição foi observado no nível de 50% e proporcionou menores percentuais de gordura abdominal (0,66%), ovário (0,60%), oviduto (0,77%) e comprimento de oviduto (32 cm). O percentual de produção de ovos foi maior no primeiro período para as aves submetidas aos métodos de 75 e 100% de restrição com 15 e 20% de redução de peso, respectivamente. Entretanto, para as aves com 50% de restrição e 25% de redução de peso, as maiores produções (86,80 e 83,20%) ocorreram no quarto e quinto períodos. A restrição alimentar qualitativa, em 50% da dieta com ração e casca de arroz, por ser menos agressiva, proporciona melhores condições de bem-estar e facilita o manejo da granja.<br>Alternative methods were assessed of qualitative feed restriction compared to the conventional forced molt technique. Four hundred and eighty Babcock hens were used distributed in three levels of feed restriction (100, 75 and 50%) and three body weight reduction percentages (15, 20 and 25%), with five replications of 32 hens. When the birds reached the body weight reduction percentage the packed cell volume, percentages of ovary, oviduct, gizzard, intestine, abdominal fat and oviduct length were determined. Starting on day 28 and during five 28-day periods the quantitative and qualitative characteristics of production after forced molt were measured. The largest restriction period occurred at 50% of restriction that resulted in the smallest percentages of abdominal fat (0.66%), ovary (0.60%), oviduct (0.77%) and oviduct length (32 cm). The egg production percentage was higher in the first period, for the 75 and 100% restriction methods with up to 15 and 20% body weight reduction, respectively. However, for the birds with 50% restriction and 25% body weight reduction, the highest productions (86.80 and 83.20%) occurred in the 4th and 5th periods. Qualitative feed restriction at 50% of the diet with feed and rice hulls, because it was less aggressive, resulted in better welfare conditions and facilitated farm management

Performance and carcass traits in the diallel crossing of pacu and tambaqui

With the purpose of evaluating the changes and the degree of heterosis on performance and carcass traits of fish from the diallel crossing between Pacu and Tambaqui, four genetic groups were generated through hormonal induction: pacu, tambaqui, tambacu and paqui. For 196 days, 400 juveniles of each genetic group were stocked in a pond divided into four parts of equal size, one for each group. At the end of this period, when the fish weighed on average 1024 g (±115.52 g), 20 specimens of each genetic group were sampled, weighed, measured: head length; standard length; body height; and width; and also processed resulting in following body yield: viscera; carcass; head; fillet; rib; residue and skin yields. There was positive heterosis for body weight, viscera and skin yield and head measures and negative heterosis for carcass and filet yield and body width, indicating that the hybrids have better performance on weight gain, but are inferior in relation to the carcass conformation