Effect of alfalfa (Medicago sativa L.) saponins on meat color and myoglobin reduction status in the longissimus thoracis muscle of growing lambs

Effects of supplementing sweet sorghum with grapeseeds on carcass parameters, and meat quality, amino acid, and fatty acid composition of lambs

OBJECTIVE

Sweet sorghum is an important forage crop for ruminants, especially in low rainfall areas. Grapeseeds are an abundant by-product of wine-making and contain bioactive substances that can improve the antioxidant capacity of meat. We examined the effect of sweet sorghum forage with supplementary grapeseeds on carcass and meat quality in lambs.

METHODS

Twenty-eight Small-tailed Han lambs (body weight = 19.1±1.20 kg), aged 3 to 4 months, were penned, and fed individually. The lambs were divided into four groups (n = 7 each) and were offered one of four diets: i) sweet sorghum silage; ii) sweet sorghum silage + grapeseeds; iii) sweet sorghum hay; and iv) sweet sorghum hay + grapeseeds. The grapeseeds were added to the concentrate at 6% DM and the diets were fed for 100 d.

RESULTS

Sweet sorghum silage tended (p = 0.068) to increase hot carcass weight, while grapeseeds tended (p = 0.081) to decrease dressing percentage without affecting other carcass parameters. Lambs consuming supplementary grapeseeds increased (p<0.05) meat redness and tended to decrease (p = 0.075) concentration of methionine in meat. Lambs consuming sweet sorghum silage increased (p<0.001) water content of the meat and had a lower (p<0.05) concentration of n-6 polyunsaturated fatty acids (PUFA) and n-6:n-3 PUFA ratio than lambs consuming sweet sorghum hay. Saturated fatty acids content in meat was lowest (p<0.05) in lambs consuming sweet sorghum silage with grapeseeds. Lambs with supplementary grapeseeds tended (p<0.10) to increase eicosapentaenoic acid and docosahexaenoic acid and have a lower thrombogenic index than lambs not consuming grapeseeds.

CONCLUSION

It was concluded that sweet sorghum with supplementary grapeseeds fed to lambs; i) improved the color of the meat to be more appetizing to the consumer; ii) tended to improve the fatty acids composition of the meat; and iii) lowered thrombogenic index of the meat.

Effects of alfalfa saponins on the production performance, serum biochemical factors, and immune factors in Small-Tailed Han sheep

This study aimed to determine the potential effects of alfalfa saponins on the production performance, serum biochemical factors, and immune factors in sheep. Twenty Small-Tailed Han sheep were equally and randomly divided into Groups 1–4, fed with diets containing 0, 5, 10, and 20 g alfalfa saponins per kg, respectively, for 40 consecutive days. During the treatments, the body weight change was recorded for each sheep. Before, during, and after the treatments of alfalfa saponins, serum was collected from each group to compare the levels of biochemical and immune factors. All sheep were killed after the treatments, and the longissimus dorsi muscle was collected to compare the meat quality. The results validated the effects of alfalfa saponins on the growth performance and meat quality in Small-Tailed Han sheep, and the supplementation level of 10 g/kg was the best. Alfalfa saponins also had effects on the levels of biochemical factors in serum. However, both dose- and time-dependent effects were observed. After a shorter feeding period (14 days), the concentrations of cholesterol (CHOL) and low-density lipoprotein (LDL) in Groups 2, 3, and 4 were all lower than those in the control group; however, when alfalfa saponins were continuously fed, this effect was not apparent or even gone. Supplying alfalfa saponins increased serum concentrations of IgA, IgG, IgE, IgM, IL-1, IFN-α, and IFN-β. And this effect was distinctly observed in Groups 3 and 4. Based on the current results, the alfalfa saponins concentration of 10 g/kg (for 14 consecutive days) could be suggested as the optimum ratio for good health conditions of Small-Tailed Han sheep.

Lipid Metabolism, Carcass Characteristics and Longissimus dorsi Muscle Fatty Acid Composition of Tropical Crossbred Beef Cattle in Response to Desmanthus spp. Forage Backgrounding

Lipid metabolism, carcass characteristics and fatty acid (FA) composition of the Longissimus dorsi (loin eye) muscle were evaluated in tropical crossbred steers backgrounded on Desmanthus spp. (desmanthus) with or without feedlot finishing. It was hypothesized that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce carcasses with similar characteristics and FA composition. Forty-eight Brahman, Charbray and Droughtmaster crossbred beef steers were backgrounded for 140 days on Rhodes grass (Chloris gayana) hay augmented with 0, 15, 30 or 45 percent desmanthus on dry matter basis. Lucerne (Medicago sativa) hay was added to the 0, 15 and 30 percent desmanthus diets to ensure that they were isonitrogenous with the 45 percent desmanthus diet. After backgrounding, the two heaviest steers in each pen were slaughtered and the rest were finished in the feedlot for 95 days before slaughter. Muscle biopsy samples were taken at the beginning and end of the backgrounding phase. Carcasses were sampled at slaughter for intramuscular fat (IMF) content, fat melting point (FMP) and FA composition analyses. Increasing the proportion of desmanthus in the diet led to a linear increase in docosanoic acid (p = 0.04) and omega-6/omega-3 polyunsaturated FA ratio (n-6/n-3 PUFA; p = 0.01), while docosahexaenoic acid decreased linearly (p = 0.01). Feedlot finishing increased hot carcass weight, subcutaneous fat depth at the P8 site and dressing percentage (p ≤ 0.04). The n-6/n-3 PUFA ratio was within the recommended < 5 for human diets. IMF was within the consumer-preferred ≥3% level for palatability. The hypothesis that steers backgrounded on isonitrogenous diets augmented with incremental proportions of desmanthus will produce similar carcass characteristics and FA composition was accepted. These findings indicate that a combination of tropical beef cattle backgrounding on desmanthus augmented forage and short-term feedlot finishing produces healthy and highly palatable meat.