Biological evaluation of rapeseed meal, soya-bean meal and casein fed to the weanling and the mature rat

Abstract

I. The biological evaluation of solvent and prepress-solvent processed rapeseed meals KM(S) and RM(PS) was carried out with the weanling (phase I) and the mature (phase z ) rat. The nutritional indices measured were compared with those for diets containing soyabean meal SM and casein CS.2. The true nitrogen digestibility (td(N)) for RM(S), RM(PS), SM and CS in the weanling rat was (%) 78.9 f 1'2,77'9 k 2.7, 90'4f 0.9 and 96.0 If: 0.6 (P < 0.01) respectively. Net protein utilization was (%) 68.9 f 10.1, 65.6f 3'5, 80.6 k4.8 and 81.7 & 3'1 (P < 0.05) respectively.Biological value was (%) 83.0 f 7'9,841 k 5.6,890 f 5.1 and 85.0 +-3.4 ( P < 0.05) respectively.The same indices when measured in the mature rat showed an increase over those obtained in the weanling rat. 3.The growth-promoting effects of the test diets were evaluated over a period of 8 weeks with ad lib. feeding between phases I and 2. Protein efficiency ratio averaged z'ofo.14, 1'9fo.35, 2.4+0'39 and 2 . 3 + 0 , 2 5 for the RM(S), RM(PS), SM and CS treatments respectively.4. The daily endogenous urinary N excretion was 1.58 f 0.14 mg N/basal kcal or 254 mg N/kg body-weight for the weanling rat and 0.16 mg N/basal kcal or 18 mg N/kg bodyweight for the mature rat. Metabolic faecal N excretion was 98.0 * 9.3 mg N/kg body-weight, or 27-9 yo of the total N output for the weanling rat, and 37.9 f 7.2 mg N/kg body-weight, or 67.3 yo of the total N output for the mature rat during the 'protein-free' feeding periods.5. The fresh weight of the thyroid gland per kg metabolic body size was 70, 90,40 and 40 mg respectively for the RM(S), RM(PS), SM and CS dietary treatments. 6.The moisture content of the carcasses was 66.9 + 3.1, 63.6 f 2.3 and 64.2 f 2.2 and the protein content on a dry-matter basis was 55.9 9.6,50.2 4 6.4 and 53.1 f 4 9 for the RM (S and PS), SM and CS diets respectively. The results suggest an increased lean body mass in the rats receiving the rapeseed meal treatments.7. Under the conditions of this experiment solvent-extracted rapeseed meal was superior to prepress-solvent meal on the basis of rat growth response and of results for nutritional indices. Both rapeseed meals were inferior to soya-bean meal and casein.Experimental work conducted in Canada and abroad on the utilization of rapeseed meal as a protein supplement has been reviewed (Bowland, Clandinin &Wetter, 1965). Information on the biological evaluation of rapeseed meal is limited and the authors of the present report are not aware of such work done with the weanling and the mature rat. Although the protein of rapeseed meal is reasonably well balanced in essential amino acids, the method of processing, the high crude fibre content (9-15 %), the level of goitrogenic compounds and the bitter taste of the meal may affect its value as a protein supplement.Experiments have been conducted in which solvent extracted soya-bean meal and vitamin-free casein served as controls for the biological evaluation of solvent or prepress-solvent processed rapeseed meals.The results obtained in this inves...

Effect of Varying Quantity and Quality of Dietary Protein Intake in Experimental Renal Disease in Rats

“…No difference was found within the experimental groups in survival between the 12 and 24% level of protein intake after 12 weeks of dietary treatment. This result is in accord with previous studies that have used similar levels of dietary protein, in that the improved survival of animals on the lower protein intake only became apparent 20 weeks after a reduction in renal mass [3,4], Vegetable proteins generally tend to be of a slightly lower nutritive value than milk proteins, a range of re ported values of 60-90% for soya compared to casein [18][19][20], In this study, animals maintained on soya diets tended in all groups towards a reduced weight gain com pared to their casein counterparts, however, only in groups A and C was this difference significant. Previous studies have shown that so^a protein has a lower true digestibility value than casein (reported range 80-90%) [19,21], with rats ingesting soya protein having lower urinary nitrogen excretion and higher faecal nitrogen excretion, despite both proteins maintaining similar rates of growth.…”

Nutritional evaluation of the protein of dried tomato pomace in the rat

“…The PER of unsupplemented DTP-20 was 2.18 and the NPU 0.55. Values previously reported for SOM-45 byDrouliscos & Bowland (1969) were PER 2-40, NPU 0.80, and the present results gave a PER of 2-20 and 2-94 for the BP-T and CS respectively…”

Effects of dietary protein on renal function and lipid metabolism in five-sixths nephrectomized rats

“…There is impressive evidence that a soyabean-protein diet may be quite effective in ameliorating uraemic symptoms and preventing some of the complications of CRF. Previous studies have shown that soyabean protein has a lower nutritive value compared with casein (Drouliscos & Bowland, 1969). However, soyabean protein is now recognized as a complete protein, using the protein digestibility-corrected amino acid score that has been adopted as an alternative method for evaluating protein quality (Food and Drug Administration, 1991;Young, 1991).…”