Desempenho e características de carcaça de cordeiros terminados com dietas contendo níveis de palma forrageira.

Abstract

The aim of this study was to avaliate the effect of inclusion levels of Nopalea cohenillifera Salm Dyck, as source water intake in Santa Inês sheep on the performance, carcass characteristics, and histological morphometry of the gastrointestinal tract. Forty two Santa Inês sheep (± 100 days, ± 18.74 kg) were used. The experimental design was a factorial arrangement (3x2) with 3 inclusion levels of spineless cactus (30%, 50% 70%) replacing the Tifton hay and subdivided into two groups, with or without access to water and a treatment control. The animals were fed ad libitum until reaching 32 kg (± 1 kg) or 90 days in confinement. There was interaction between water availability and spineless cactus replacement levels only for total water intake. The dry matter intake decreased (P <0.05) with the inclusion of spineless cactus in the diets, presenting a lower intake at the level of 70% forage palm inclusion in the diet. The intake of organic matter, crude protein, neutral detergent fiber, ethereal extract and total carbohydrates differed between treatments (P <0.05), with higher intakes at the 30% forage spineless cactus inclusion level and the control treatment , and the lowest intake with the 70% treatment. Voluntary water intake decreased (P <0.05) with inclusion of spineless cactus in diets, but water intake through food and total water intake increased with inclusion of spineless cactus (P <0.05). The daily weight gain was higher for treatments with 30 and 50% of spineless cactus, with gains of 174 and 155 g, respectively. In the carcass characteristics, no significant interaction between the effect of spineless cactus and water restriction was observed for any of the evaluated variables of the carcass characteristics. The influence of the inclusion of spineless cactus relative to the control treatment was different for variables: empty body weight, gastrointestinal tract content, hot carcass weight, cold carcass weight, true yield and carcass compactness index. There were no significant differences between spineless cactus in the diet for commercial cuts. There was no significant difference of the water restriction on the weights of commercial cuts. Differences were found between the control treatment and the use of spineless cactus in the diets, observing smaller weights for the control xvii treatment. Reconstituted leg weights, muscle yield, bone, fat, other tissues, and leg muscularity index were not influenced by the inclusion of spineless cactus in diets nor by water restriction. The inclusion of forage spineless cactus in the diet has a significant effect on the weight of the heart, liver, spleen, head and skin in relation to the treatment. It was observed a greater length of ruminal papilla in the treatments using spineless cactus. The interaction between water and treatment had a significant effect, observing a higher papilla length with 70% of spineless cactus and water supply, and the opposite effect was observed for the 30% treatment. The width of the ruminal papilla was greater for the control treatment and 70%. The thickness of the ruminal musculature increased with the addition and greater proportion of the spineless cactus. The height of the intestinal mucosa decreased with 70% treatment. The spineless cactus can be used with or without water restriction in feed of Santa Inês sheep since it improve the performance of the animals, the characteristics of the carcass and viscera weight, without modifying the yield of the cuts, in addition it improves the ruminal morphometry of the sheep, being recommended its use.