Methionine supplementation of processed soybeans in the rat

Feeding differently processed soya bean. Part 1. Effect on performance, protein utilization, relative organ weights, carcass traits and economics of producing broiler-chickens

The comparative utilization of differently processed (roasted, cooked and oil cake) soya bean base diets and groundnut cake diet were evaluated in a feeding trial using 100 day-old Anak broiler-chicks. The response criteria included performance, protein utilization, relative organ weights, carcass traits and economy of production. At the end of the feeding trial, the average weight gains of chicks fed processed soya bean diets were significantly (P less than 0.05) higher than those fed groundnut cake and raw soya bean diets. Both feed consumption and efficiency were significantly (P less than 0.05) enhanced by processing. For example, feed consumption was highest in the chicks fed soya bean oil cake and least in those fed raw bean. Feed efficiency was best in chicks fed roasted soya bean. The relative weights [g/100 g body wt.] of the liver, kidneys, lungs, heart, gizzard and bursa were not significantly affected by the differently processed soya bean while the raw bean (unprocessed) significantly (P less than 0.01) increased pancreas weight. The dressed weight [%], eviscerated weight [%] and the relative weight of the thigh, drumsticks, chest, back and head were not significantly influenced by the dietary treatments. However, the relative weights of the shank and belly fat were significantly (P less than 0.05) affected. Cost-benefit analysis showed that the processed soya bean gave higher profit than groundnut cake diet. Among the soya bean diets, profit was in the order: roasted greater than cooked greater than oil cake greater than raw bean.

Effect of variable protein contents in diets containing Phaseolus vulgaris beans on performance, organ weights and blood variables in piglets, rats and chickens

A comparison was made of the effects of antinutritional factors present in Phaseolus vulgaris on piglets, rats and chickens. Also the hypothesis of whether the negative effect on weight gain due to the inclusion of raw Phaseolus vulgaris in the diet can be attributed to an insufficient supply of amino acids was tested. Test diets containing 200 g raw Phaseolus beans/kg were balanced for digestible protein and amino acids; in one diet extra casein was incorporated. The main response criteria were live-weight gain and the weight of various organs including the intestine. Live-weight gain in piglets was markedly reduced during feeding 200 g raw Phaseolus vulgaris/kg in the diet, but not in rats and chickens. Addition of casein did not improve the weight gain of the piglets, indicating that a toxic factor was responsible for the reduced weight gain and not an insufficient supply of amino acids. The weights of the spleen and thymus were markedly reduced in the piglets when the diets with raw Phaseolus beans were given, but not in the rats and chickens. Additional supply of casein did not change this effect. Indications were found that when the supply of dietary protein is adequate there is no reduction in pancreas weight with raw Phaseolus beans as was observed in previous experiments. The weight of the intestine was increased in all three species due to feeding raw Phaseolus vulgaris.

Nutritional improvement of legume proteins through disulfide interchange

Treatment of raw soy flour with L-cysteine or N-acetyl-L-cysteine results in the introduction of new half-cystine residues into sulfur-poor legume proteins, with a corresponding improvement in nutritional quality as measured by the protein efficiency ratio (PER) in rats. The proteins are modified through formation of mixed disulfide bonds among added sulfhydryl compounds, proteolytic enzyme inhibitors, and structural legume proteins. This modification leads to loss of inhibitory activity and increased protein digestibility and nutritive value. Sodium sulfite is more effective than cysteine in facilitating inactivation of trypsin inhibitors in soy flour. The synergistic effect of sodium sulfite and heat may be due to ability to induce rearrangement of protein disulfide bonds to produce new structural entities without altering the amino acid composition and to the fact that the new structures lose their ability to complex with trypsin or chymotrypsin. The same treatment inactivated hemagglutinins (lectins) in lima bean flour. These considerations suggest a key role for sulfur amino acids in the nutritional quality and safety of legumes.

The effect of raw soya bean on in vitro active and passive accumulation by rat small intestine

1. Sections of small intestine from rats given raw-soya-bean(RS) diets had a decreased capacity to actively accumulate L-methionine when compared to those taken from rats given heated soya bean (HS), and casein-fed controls. The extent of the reduction was small in comparison with pair-fed animals, but was statistically significant in comparison with rats restricted to the same weight gain as the RS groups. 2. The differences in the passive uptake of D-mannitol appear to be directly related to differences in gut thickness between the control and RS groups. 3. Values for water movement and intestinal transmural potentials further support the results found in the active accumulation studies. 4. From this study it was concluded that the degree of starvation directly affects the magnitude of the effect of RS diets when comparisons are made against adequately fed controls.

The effect of methionine supplementation on the levels of pancreatopeptidase E, trypsin, chymotrypsin and amylase in the pancreas of chicks receiving raw and heated soya-bean diets

1. The effect of methionine supplementation upon pancreatic trypsin, chymotrypsin, pancreatopeptidase E and amylase of chicks given raw and heated soya-bean diets (RSD and HSD) was studied before and after fasting.

2. Statistical analysis of the ratios of amylase to pancreatopeptidase E, trypsin and chymotrypsin in each individual chick revealed that methionine supplementation consistently increased the ratio of amylolytic to proteolytic enzymes. This phenomenon was most marked in the fasted RSD group, less in the fed RSD and fasted HSD groups and least in the fed HSD group.

3. The results are discussed in relation to methionine metabolism in chicks given RSD and HSD supplemented with trypsin inhibitors.