Saponins are common in a large number of plants and plant products. It is having important role in human and animal nutrition. Saponins have biological role as membrane-permeabilising, immunostimulant and hypocholesterolaemic properties and it has found to have significant affect growth and feed intake in animals. These compounds have been observed to kill protozoans, to impair the protein digestion and the uptake of vitamins and minerals in the gut and to act as hypoglycemic agent. These compounds thus affect animals in both positive and negative ways.

SU MMARYDiets for broiler chickens (n=90) were supplemented with chromium (CrCl 3 , 6H 2 O), either alone (0 . 2 mg/kg diet) or in a combination with ascorbic acid (0 . 2 mg Cr and 50 mg ascorbic acid/kg diet). The objectives of the study were to ascertain if ascorbic acid had any additive effect on the actions of chromium and whether chromium supplementation could alleviate the nutritional stress in the birds imposed by a reduced energy intake. The birds were fed at the recommended (Bureau of Indian Standards 1992) and at a lower plane of energy. Live-weight gain and diet utilization were higher (P<0 . 01) when the normal energy diet supplemented with chromium was fed. Food intake (35 days) was higher (P<0 . 001) in the birds fed with the low energy diet. There was an increase (P<0 . 01) in metabolizability due to the supplementation of chromium. The metabolizability of crude protein and total carbohydrate increased (P<0 . 05) when chromium and ascorbic acid were supplemented together. Chromium intake was higher (P<0 . 001) in the supplemented birds, especially in those fed with the low energy diet (P<0 . 05), though its retention was higher (P<0 . 05) when the normal energy diet was given. Chromium in combination with ascorbic acid also enhanced (P<0 . 01) chromium retention. Blood glucose (P<0 . 001) and plasma cholesterol (P<0 . 05) were lower in the supplemented birds and blood glucose was reduced further when ascorbic acid was supplemented together with chromium (P<0 . 01). Plasma protein increased (P<0 . 05) in the supplemented chickens. However, variation in the dietary energy concentration did not exert any significant effect on these blood parameters. Plasma chromium was higher (P<0 . 05) in the supplemented birds, though chromium had little effect in this regard with ascorbic acid. Plasma copper increased (P<0 . 05) when chromium was supplemented alone and increased further (P<0 . 05) when chromium and ascorbic acid were supplemented together. Deposition of chromium in the breast and thighs increased (P<0 . 05) due to supplementation. Protein content and total accretion of protein in the carcass were higher (P<0 . 05) when chromium was supplemented alone and with ascorbic acid. The supplemented birds had less (P<0 . 01) fat per 100 g of carcass irrespective of the dietary energy concentration. Weight of the hot carcass increased (P<0 . 05) due to chromium supplementation although dietary energy concentration did not affect this particular parameter. It was concluded that inorganic chromium supplementation (0 . 2 mg chromium/kg diet) might effectively enhance the growth performance, diet utilization and carcass characteristics in broiler chickens. Addition of ascorbic acid might also be beneficial in this regard. However, dietary energy concentration was more critical and to yield the maximum benefit of Cr supplementation in broiler chickens, an optimum level was essential.

An on-farm trial was conducted to ascertain the effects of chromium supplementation on the nutrient utilization and reproductive performance of cross-bred (Bos taurus × Bos indicus) prepubertal anestrous dairy heifers. Chromium was supplemented (0, 0.25, 0.5 and 1.0 mg kg −1 diet dry matter) as chromium chloride hexahydrate or chromium-yeast complex. The intake of the total digestible nutrients (P < 0.01) and body weight gain (P < 0.05) increased with supplementation of chromium. Chromium-yeast supplementation resulted in a dose-dependent increment (P < 0.01) in the total digestible nutrient intake. Intake and apparent absorption of chromium increased linearly (P < 0.001) with the dose. Chromium chloride tended to be better absorbed (P < 0.10) than the chromium-yeast complex. The source of supplemental chromium did not affect the plasma concentrations of glucose, cholesterol, total protein and albumin. The postprandial plasma glucose concentration in the control group increased by 38% versus 0.27 and 1.1% in the heifers supplemented with 1.0 mg Cr kg −1 dry matter as chromium chloride and chromium-yeast complex, respectively. The postprandial increment in the plasma cholesterol was also generally lower in the supplemented heifers. The plasma chromium concentration varied (P < 0.05) between the groups, although it was difficult to correlate these changes with the sources and doses of supplemental chromium. Chromium chloride and chromium-yeast supplementation resulted in similar changes in the plasma concentrations of copper, zinc, iron and manganese (P > 0.05). Plasma concentrations of copper and zinc, which increased (P < 0.001) with chromium supplementation, declined quadratically (P < 0.05) as the dose of supplemental chromium increased. At the end of the supplementation, two, four and three heifers fed with 0.25, 0.5 and 1.0 mg Cr kg −1 dry matter (as chromium chloride), respectively, developed Graffian follicles and showed estrus; the numbers were one, three and four in the corresponding groups fed with chromium-yeast complex and one, two and three heifers amongst them showed estrus. All the supplemented animals showing estrus conceived and no abortion was reported during the first trimester of their pregnancy. It was concluded that chromium supplementation could appreciably enhance the nutrient utilization and the reproductive performance in anestrous dairy heifers and inorganic trivalent chromium (CrCl 3 .6H 2 O) supplementation might be as useful as a chromium-yeast complex for this purpose.

Castrated male black Bengal kids were supplemented daily with 0, 0·5, 1·0, 1·5 and 2·0 mg chromium (Cr3+ as chromic chloride hexahydrate) for 150 days. Metabolic stresses such as a feeding challenge, an intravenous glucose tolerance test (IVGTT) and a short-term (72 h) feed deprivation were imposed on the animals to ascertain if supplemental Cr could alleviate these stresses and whether the stress-alleviating effect could provide an explanatory basis for the performance traits of the supplemented animals. The kids were fed with a concentrate diet containing 0·197 mg Cr/kg DM. DM intake (g/kgw0·75) was lower (P=0·006) in the 0·5 and 1·5 mg groups. Feed efficiency tended (P=0·086) to improve in the Cr-supplemented kids, although a distinct dose response was absent. Basal serum T3 increased linearly (P=0·01) with increased dose of Cr although the post-prandial change did not follow any definite trend. Basal serum insulin increased (P=0·001) linearly while the post-prandial increment was higher (P=0·037) in the control group. The IVGTT indicated that the kids supplemented with 1·5 mg Cr had significantly (P<0·05) higher serum clearance rate and lower half-life for insulin. Serum Cr during the IVGTT declined (P<0·05) until 45 m after glucose infusion and then increased again (P<0·10) at 60 m in the 0·5 and 1·5 mg groups although in the rest of the experimental groups serum Cr was stable during the entire course of the IVGTT. The body weights at the beginning of the fast were higher (P=0·036) in the kids supplemented with 0·5 and 1·5 mg Cr. However, the change in body weight at the end of the 72 h fast did not vary (P>0·10) between the groups. Cr supplementation reduced (P<0·05) serum cortisol level in the supplemented animals consistently throughout the duration of the feed deprivation. Moreover, as the fast progressed serum cortisol tended to increase (P=0·059) in all the experimental groups irrespective of the level of Cr supplementation. It was concluded that inorganic Cr supplementation might appreciably increase serum T3 concentration and reduce the level of cortisol which might augment animal productivity. However, further research with a more sensitive design is required to establish the exact level of Cr supplementation for enhancing performance of livestock.

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