No abstract

The objective of the study was to determine the effects of two enzyme preparations containing beta-glucanase and xylanase activities on barley- and wheat-based diets, respectively, for broilers, in combination with flavomycin. In addition, the stability of the enzyme preparations after pelleting was measured. Temperatures recorded during the pelleting process reached 75 to 80 C, and the activities recovered with respect to the amounts present in the mash feed before pelleting were 80% or higher. Two performance experiments were conducted simultaneously under the same conditions over 6 wk. In addition, intestinal viscosity and incidence of vent pasting were measured and carcasses were eviscerated to determine abdominal fat, carcass yield, and percentage weight of intestines and viscera. Twenty-four pens (12 per sex), each containing 75 chickens were used in each experiment. Wheat- or barley-based diets were supplemented with flavomycin and a xylanase or a beta-glucanase preparation, respectively, in a 2 x 2 factorial arrangement of treatments. In the wheat diets, xylanase and flavomycin improved feed efficiency, in parallel with a reduction of intestinal viscosity. Xylanase reduced the incidence of vent pasting and the percentage viscera, especially of intestines, and increased abdominal fat. In the barley diets, beta-glucanase and flavomycin improved feed conversion. beta-Glucanase also reduced intestinal viscosity and vent pasting. Both beta-glucanase and flavomycin reduced percentage intestines, but the effects were not additive. In general, the effects of the enzyme preparations and flavomycin were independent, except for percentage intestines with beta-glucanase.

No abstract

This study was conducted to determine whether the level of chromic oxide supplemented to diets containing gelatinized starch as the carbohydrate source affects digestibility, body composition, growth performances, and liver enzyme activities in gilthead sea bream, Sparus aurata. Gilthead sea bream fingerlings were fed diets containing gelatinized corn starch as the carbohydrate source and several levels of chromic oxide (0, 5, 10 and 20 g/kg) for 6 wk. No effect of dietary chromium level was detected on carbon, nitrogen, or dry matter digestibility. Calcium and phosphorus digestibility were higher in fish fed the diet supplemented with 5 g/kg chromic oxide than in fish fed the other supplemented diets. Dietary chromium did not affect dry matter, carbon, nitrogen, protein, or lipid concentrations in fish. However, fish fed 5 g/kg chromic oxide generally had higher levels of calcium, phosphorus, and ash than fish fed the other Cr-containing diets. Chromium concentration was significantly higher in fish fed the diets with 0.5 and 1% chromic oxide than in fish fed the control diet. Chromium supplementation of the diets did not affect the specific growth rate, the food efficiency ratio, the protein efficiency ratio, or, protein or nitrogen retention of the fish. Blood glucose and the activity of several liver enzymes involved in carbohydrate metabolism were unaffected by dietary chromic oxide. Alanine aminotransferase was lower in the fish fed the diet with 10 g/kg of chromic oxide than in unsupplemented controls. Our results indicate that chromic oxide can be used as a neutral marker in fish nutrition studies involving organic compounds, but not mineral salts.

The absorption of carbon, nitrogen, phosphorus and dry matter along the intestine of Sparus aurata has been measured and the reliability of different methods to estimate apparent digestibility coefficients has been evaluated. 1996 The Fisheries Society of the British Isles