The effect of energy intake of gilts on the supply of metabolizable energy and protein deposition.

Abstract

Two trials with 16 gilts of 35 kg and 16 gilts of 64 kg were made. Rations were prepared by mixing two basal feeds in different ratios. Four different energy levels were used in which energy was expressed as multiples of maintenance (M) requirement (treatments: 1 = 2.8 to 3.0 M; 2 = 2.4 to 2.6 M; 3 = 2.1 to 2.2 M; 4 = 1.8 to 1.9 M). Digestibility of energy was not influenced by treatment (mean 83.5%). Feed components (except protein) were better digested in pigs at a larger weight (e.g., energy 3.2 and crude fibre 5.7 percentage units). Rations of weight class 2 were based on a different ratio of the basal feeds than the rations of weight class 1. Metabolizable energy content of the ration was similar for the four diets (mean 12.4 kJ/g). After correcting for differences in feed composition the metabolizability tended to be slightly depressed at the high levels of energy intake. Protein gain was determined for each gilt. Protein and fat gains were calculated from the rate of gain and daily energy intake at the same amount of digestible protein intake. Protein gain was reduced at a level of energy intake below 2.5 M. Fat gain was influenced more by feeding level than protein gain. Fat gain was diminished when energy intake was reduced. (Abstract retrieved from CAB Abstracts by CABI’s permission)