Influence des traitements technologiques sur l'utilisation des protéines de la féverole par le veau préruminant

Open Access
Publisher Website
Google Scholar
Abstract
The utilization of 5 products prepared from dehulled field-beans (raw, flaked, micronized field beans or protein enriched either by air-classification or by fermentation with Saccharomyces carlsbergensis) was studied in the preruminant calf. Digestibility of milk replacers in which these products supplied 41% (raw, flaked and micronized field beans), 50% (air-classified field bean) or 75% (fermented field-bean) of the proteins, was measured in a series of balance trials. The rest of the protein was supplied by whey powder (fermented field bean diet) or by skim milk (other diets) and synthetic amino acids. Fermented field bean was compared with soybean meal fermented by the same yeast. The appetite of the animals was only satisfactory with the field-bean and feremnted soybean diets. The apparent digestibility of raw field bean N was low (0.72); flaking, air-classification and fermentation led to an increase of this digestibility in very similar proportions, but the most favorable effect was obtained with micronization (0.83). The digestibility of fermented soybean (0.79) was the same as that of the corresponding field bean. Examination of the amino acid composition of the feces revealed that they only contained a small proportion of dietary proteins; this was mainly due to microbial digestion in the large intestine since rather nonnegligible amounts of dietary proteins were present in the distal part of the ileum, at least in the case of raw, flaked and micronized field-beans. The fraction of dietary proteins seemed to be smaller in that part of the intestine, with micronized field bean. The increase in the apparent digestibility of field bean N, caused by micronization seems at least partly to be due to an improvement of its true digestibility. The effect of replacing a part of the milk proteins by those of raw, micronized or fermented field beans, proteins were exclusively supplied by skim milk powder. In the 3 other diets, the field beans studied provided 14% of the digestible proteins, the rest being supplied by skim-milk powder and synthetic amino acids. Each of these diets was offered to 12 Friesian male calves between the ages of .apprx. 15 and 113 days. Live weight gain, feed efficiency and commercial dressing out were significantly lower with the raw field bean diet than with the control diet. Micronization and especially fermentation contributed to reducing but not to eliminating the alteration of growth and feed efficiency. None of the processings studied seemed to give products that were usable as a large protein fraction in milk replacers for preruminant calves.
Keywords