The digestion of untreated and formaldehyde-treated soya-bean and rapeseed meals by cattle fed a basal silage diet

Abstract

The effect of pretreating soya-bean and rapeseed meals with formaldehyde was studied. Soya-bean and rapeseed meals, both untreated and formaldehyde-treated, were fed to cattle receiving a basal diet of silage in a 4 x 4 latin square. Formaldehyde treatment of both meals significantly reduced apparent N digestibility. All four protein supplements increased the amounts of non-ammonia N and amino acid N entering the small intestine over those obtained when silage was fed alone. Formaldehyde treatment of the meals increased the amounts of non-ammonia N and amino acid N entering the small intestine; this effect was significant, however, for only the formaldehyde treatment of the soya-bean meal. The low efficiency of microbial N synthesis observed when silage was fed alone was increased by the inclusion of both of the soyabean meals in the diet but not by the inclusion of the rapeseed meals. Formaldehyde treatment reduced the apparent degradability of the soya-bean meal N, determined in vivo, from 0-90 for the untreated meal to 0-40 for the formaldehyde-treated meal; similarly the degradability of the untreated rapeseed meal was reduced from 0-77 to 0-41 by the formaldehyde treatment. The in sacco technique gave values for degradability for the protein supplements which ranked them in a similar manner as did the in vivo technique; however, for any one meal the in sacco value for degradability was lower than that determined in vivo.

Effect of Protein Intake on Gastrin Secretion in Ruminants

“…Digesta was not sampled in the sheep, but from theoretical considerations, rumen degradation values of dried grass (0f85; Coelho da Silva, Seeley, Thomson, Beever & Armstrong, 1972), barley (0-80;Agricultural Research Council, 1980) and fishmeal/barley (0f42-0 56) and soyabean meal/barley (0 47-070; Ling & Buttery, 1978) indicates that the HP diet would be expected to increase the proportion of dietary protein reaching the post-ruminal tract compared with the LP diet. Indeed the formaldehyde treatment of soyabean meal used in this study has been shown to decrease the 'in sacco' degradability of soyabean meal, albeit in cattle, from the untreated value of 0-90 to 040 (Rooke, Brookes & Armstrong, 1983), which would further enhance the difference in quantities of undegraded dietary protein reaching the abomasum, the major site of gastrin G cells (Bunnett, 1984). The lack of difference in gastrin responses between diets in the sheep experiment suggests either that, once modified by rumen fermentation, the protein content of the diets was not sufficiently different to produce dissimilar gastrin responses or that there is less of a reliance on protein and its products of digestion for stimulation of gastrin release than there is in non-ruminant species.…”

Protein supplementation of formic acid‐ and enzyme‐treated silages. 1. Digestibilities, organic matter and fibre digestion

“…Similarly, supplementation with protein increased ammonia concentrations with both treated silages. Rooke et al (1983a) also found increased rumen ammonia levels when formic acid silage was supplemented with rapeseed meal. Molar proportions of acetate were significantly lower with enzyme-treated silage diets.…”

The effect ofin saccorumen incubation of a grass silage upon the total and D-amino acid composition of the residual silage dry matter

“…and N contents of the silage residues from the polyester bag incubations and rumen bacteria were determined according to Rooke, Brookes & Armstrong (1983). The silage residues from each pair of duplicate polyester bags were bulked prior to determination of their N and amino acid contents.…”