Modulating the lipid profile of beef using cottonseed and crude glycerin.

The search for healthy food leads to demand for functional foods that do not harm the health of the consumers. The objective was to evaluate the impact of the supply of cottonseed and crude glycerin as modulators of the lipid profile of the beef produced on pasture. The concentrated supplement was formulated with two levels of cottonseed (0 and 25%) and/or two levels of crude glycerin (0 and 15%), totaling four experimental groups. Two experiments were conducted; the first experiment was outlined in a 5 × 5 Latin square design, contrasting the protein-energy supplementation with the mineral supplementation. The concentrate supplementation allowed the increase in intake and digestibility of the dry matter (P = 0.03), ether extract, crude protein, and non-fibrous carbohydrate (P < 0.01). However, the results showed no effect of crude glycerin or cottonseed inclusion on intake or nutrients digestibility. The second experiment evaluated the protein-energy supplementation and its impact on the lipid profile of meat produced, carcass characteristics, and animal performance. There was no influence of cottonseed or crude glycerin in performance or carcass characteristics. However, the use of the cottonseed reduced the content of short-chain fatty acids, omega 3 linolenic acid, conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P < 0.01), and the inclusion of crude glycerin led to increased conjugated linoleic acid (CLA) C18: 2 cis 9 trans 11 (P = 0.04). An important result is given by illustrating the impact of these fatty acids in the nutritional quality of the meat. Thus, it is possible to manipulate the lipid profile of meat produced by cottonseed or crude glycerin supplementation, without affecting the animal performance.

Toxic inhibition of some dehydrogenases by methyl sterculate--a natural occurring substance in cotton seeds.

According to the present study, crude preparations of rainbow trout liver and rabbit muscle lactate dehydrogenase (LDH,EC 1.1.1.27) were not inhibited by methyl sterculate and oleate, while trout liver glucose-6-phosphate dehydrogenase (G6PDH,EC 1.1.1.49) was activated by these esters. Methyl sterculate inhibited purified preparations of trout liver, rabbit muscle, and bovine heart LDH in contrast to methyl oleate which inhibited only a portion of the activity of purified rabbit muscle LDH and had no appreciable effect on the activities of the other purified LDH preparations. Trout liver LDH preparations were not inhibited by p-Chloromercuribenzoate (pCMB), while rabbit muscle and bovine heart LDH were sensitive to the presence of this inhibitor. Trout liver G6PDH was activated at the lower concentrations of pCMB. These data suggest that the reduction of the activities of liver dehydrogenases in the rainbow trout fed a diet containing methyl sterculate was not due to inhibition of these dehydrogenases by this cyclic fatty acid.