Effects of organic chromium supplementation to finishing lambs diet on growth performance, carcass characteristics and meat quality

The objective of this study was to evaluate supplemental organic chromium（Cr） to finishing lambs on growth performance, carcass characteristics, and meat quality. Eighteen Suffolk lambs（age（4.5±0.2） mon;（25.8±3.6） kg body weight（BW）） were randomly assigned to three levels of supplemental organic Cr（0.0, 0.2 and 0.4 mg kg^–1 dry matter（DM）） in a complete random design. Growth performance was evaluated for 70 d, and then lambs were slaughtered to study carcass characteristics and chemical composition of meat. Orthogonal contrasts were performed（contrast one-average level 0.2 ppm Cr vs. average level 0.4 ppm Cr; contrast two-level 0 vs. average levels（0.2＋0.4） ppm Cr）. Orthogonal polynomials were used to estimate the linear and quadratic effects of Cr concentrations. Growth and carcass performance were not affected by supplemental organic Cr. Muscle conformation and leg perimeter linearly increased（P〈0.05） as organic Cr level increased in the diet. Kidney fat decreased linearly（P〈0.05） as supplemental Cr increased. In Longissimus dorsi（LD）, the ash content decreased linearly, and shear force（kg cm^–2） increased（P〈0.05） as organic Cr level increased in the diet. It is concluded that organic Cr did not affect growth performance, but it improved positively the muscle conformation, reduced kidney fat, whereas in LD there was an increment in shear force in finishing carcass lambs.

Effects of feeding yeast(Saccharomyces cerevisiae), organic selenium and chromium mixed on growth performance and carcass traits of hair lambs

Yeasts and organic minerals are used in diets to improve health, productive performance and some carcass characteristics of ruminants and non-ruminants. Thirty-two lambs（Pelibuey×Katahdin; BW=（30.55±1.67） kg; n=8） were used in a 56-d feeding experiment to study the effects of different levels of live yeast（Saccharomyces cerevisiae; yeast）, selenium（Se） and chromium（Cr） mixed（Se-Cr）, and a mixture of yeast-Se-Cr on growth performance and carcass traits. Animals were stratified by body weight（BW） and randomly assigned to one of four treatments： 1） control group（0.0 g kg–1 yeast）; 2） yeast（1.50 g kg–1 dry matter intake（DMI） d–1）; 3） Se-Cr premix（1.5 mg kg–1 DMI d–1 for each mineral）; and 4） yeast-Se-Cr mixture. There were no treatment effects on final BW; whereas lambs fed Se-Cr or yeast-Se-Cr had higher（P〈0.05） DMI than animals supplemented with only yeast. Average daily gain（ADG）, gain：feed ratio, chop area, dorsal fat and carcass yield were similar（P〉0.05） among treatment groups. In conclusion, supplementation with yeast, Se-Cr mixed or yeast-Se-Cr did not improve ADG, final BW, back fat content and carcass yield of growing of Pelibuey×Katahdin lambs. Supplementation with Se-Cr and yeast-Se-Cr increased DMI, and approximately 250 g ADG animal–1 d–1 was produced with no negative effects on growth and health of the animals.

Cr(Ⅵ) reduction capability of humic acid extracted from the organic component of municipal solid waste

The capacity of humic acid extracted from organic waste （HAw） to reduce Cr（Ⅵ） was tested at pH 2.5,4 and 6 and compared with coal-derived humic acid （HAc）.HAw was more effective than HAc in reducing Cr（Ⅵ）.The kinetics of Cr（Ⅵ） reductions depended strongly on pH.The calculation of the apparent rate coefficients indicated that HAw was more efficient at reducing Cr（Ⅵ） than HAc,but was also more efficient than HAs from soil and peat.The reduction capability of HAs depends on the type of functional groups （i.e.,thiols and phenols） present,rather than the free radicals.HAw was more efficient at reducing Cr（Ⅵ） than HAc because more reactive phenols were present,i.e.,methoxy-and methyl-phenols.