Tissue accumulation and urinary excretion of Cr in chromium picolinate (CrPic)-supplemented lambs.

Chromium (Cr) concentrations in liver, kidney, spleen, heart, lymph node, skeletal muscle, bone, testis and urine of lambs were measured to trace the biodistribution and bioaccumulation of Cr after oral supplementation with chromium picolinate (CrPic). Twenty-four Santa Inês lambs were treated with four different concentrations of CrPic: placebo, 0.250, 0.375 and 0.500 mg of CrPic/animal/day for 84 days. The basal diet consisted of Panicum maximum cv Massai hay and concentrate. Cr concentrations were measured by ICP-MS measuring (52)Cr as collected mass. There was a positive linear relationship between dose administered and the accumulation of Cr in the heart, lungs and testis. Urinary excretion of Cr occurred in a time and dose-dependent manner, so the longer or more dietary Cr provided, the greater excretion of the element. As some non-carcass components (such as lungs or heart) are added to bone and visceral meal to feed animals, there is a risk of bioaccumulation and biomagnification due to Cr offered as CrPic in the diet.

Blood Parameters and Toxicity of Chromium Picolinate Oral Supplementation in Lambs.

The effects of oral supplementation of chromium picolinate (CrPic) on various blood parameters and their possible toxicity on the liver, kidneys, lungs, heart, and testis were investigated. Twenty-four Santa Inês (SI) lambs were treated with four different concentrations of CrPic (six animals/treatment): placebo, 0.250, 0.375, and 0.500 mg CrPic/animal/day for 84 days. The basal diet consisted of hay Panicum maximum cv Massai and concentrate. Blood and serum were collected fortnightly for analysis. On day 84, the animals were euthanized, and histopathological analysis in the liver, kidney, heart, lung, and testis was made. The liver and kidney were also submitted to electronic microscopy analysis. Differences between treatments (P < 0.05) were observed for packed cell volume (day 84), hemoglobin (day 84), total plasm protein (day 56 and day 84), and triglycerides (day 70). There was no statistically significant relationship between Cr supplementation and histopathology findings, although some animals treated with supplementary Cr showed morphological changes in the liver, kidney, and testis. Thus, the effectiveness of supplementation with Cr remains in doubt as to its physiological action and toxicity in sheep.

Methane emission of Santa Inês sheep fed cottonseed by-products containing different levels of gossypol.

The aim of this study was to evaluate the methane (CH4) emission of Santa Inês sheep fed cottonseed by-products, verifying if the gossypol content of these feedstuffs affects CH4 emission. Twelve late-lactating Santa Inês sheep (44.8 ± 7.5 kg body weight (BW)) were allocated in metabolic cages for an experimental period of 19 days, 14 days for adaptation and 5 days for measuring CH4 emission and dry matter intake (DMI). The animals were divided into four treatments, established in accordance with the cottonseed by-product used in concentrate formulation: Control (CON - no cottonseed by-product), Whole cottonseed (WCS), Cottonseed cake (CSC), and Cottonseed meal (CSM). The free gossypol level of the concentrates were 0, 1,276, 350, and 190 ppm for CON, WCS, CSC, and CSM, respectively. Also, the animals received Cynodon dactylon cv. Coast Cross hay, water, and mineral salt ad libitum. The ether extract content of the diets was balanced between treatments by including soybean oil in concentrates. The technique used to measure the CH4 emission was the sulfur hexafluoride (SF6) tracer technique, and the gas samples collected were quantified by analysis in gas chromatography system. The CH4 emission was evaluated considering the daily emission (g CH4/day); DMI (g CH4/kg DMI); and BW (g CH4/kg BW). No statistical difference was found (P > 0.05) between treatments for DMI and CH4 parameters. In the regression analysis, no significant relation (P > 0.05) between gossypol content and CH4 emission was observed. These results suggest that gossypol does not affect rumen methanogenesis.