Utilization of salts of volatile fatty acids by growing sheep

Abstract

I . An experiment is reported in which groups of six lambs were fed two basal diets supplemented at three levels with a mixture of sodium and calcium acetates.2. The basal diets were given in amounts that provided equal intakes of digestible organic matter and crude protein. One contained 85 % of concentrates (Hc), the other 40% of concentrates (Lc). Rumen contents from a sheep receiving diet Hc contained a lower molar proportion of acetate and higher proportions of propionate and butyrate than when diet Lc was given.3. The calculated metabolizable energy of the basal Hc diet was utilized more efficiently than that of the basal Lc diet, for promoting empty body-weight and carcass-weight gains.4. On both basal diets, lambs receiving the diets supplemented with acetate made greater live-weight, empty body-weight and carcass-weight gains than lambs given unsupplemented diets. The responses of weight gain to increasing levels of acetate were linear.5 . The responses to acetate were greater when it was given with the Hc diet than with the Lc diet. This effect was most marked for live-weight gain ( P < o.oor), intermediate for empty body-weight gain ( P < 0 . 0 5 )~ but not significant for carcass-weight gain. This order of effects was in part due to a greater weight of alimentary tract tissue, and its contents, in lambs fed the Hc diet supplemented with acetate. 6. It is concluded that under certain circumstances the energy of acetate may be utilized less efficiently than energy from propionate or butyrate.Conflicting results have been recorded from experiments in which the utilization of acetate for growth has been compared with that of propionate or butyrate. Armstrong & Blaxter (1957) and Armstrong, Blaxter, Graham & Wainman (1958) found that when acetic acid was infused into the rumen of sheep, its utilization for lipogenesis was less than that of propionic or butyric acid. Poor utilization was associated with a high heat increment, some of the reasons for which were indicated by McClymont (1952).In previous experiments of this series where salts of volatile fatty acids (VFA) were fed to growing lambs, 0rskov & Allen (1966a, b, c) and 0rskov, Hovel1 & Allen (1966) found no differences in the efficiency of utilization of energy from salts of different acids. In one experiment (0rskov & Allen, 1 9 6 6~) a high-roughage diet promoted lower weight gains than a high-concentrate diet; associated with this effect was a greater molar proportion of acetic acid in the rumen liquor of lambs fed the high-roughage diet. It was postulated that the poorer utilization of energy in this experiment might be associated with losses of energy in the formation of acetic acid rather than in its subsequent utilization.

Interactions of alfalfa hay and sodium propionate on dairy calf performance and rumen development

“…Lee-Rangel et al (2012) reported that inclusion of calcium propionate in the diets of lambs had no effect on their feed conversion. These observations suggest that the ME supplied by VFA is more efficiently utilized than the same amount of ME supplied by the diet (Poole and Allen, 1970). Inclusion of sodium propionate in diets increased (P = 0.01) weaning age in the current study.…”

Suboptimal maternal nutrition during early fetal kidney development specifically promotes renal lipid accumulation following juvenile obesity in the offspring

“…In contrast, lean offspring remained at pasture and had unrestricted physical activity. It is possible that differences in the amount of roughage consumed between pasture and barn-reared animals may have contributed to differences in the ratio of volatile fatty acid production (Poole and Allen 1970). Any such effects in the present study did not appear to have a major effect on glucose homeostasis, because this was comparable between all groups of animals when they were maintained on the same diet ).…”