Effect of zinc source on performance, zinc status, immune response, and rumen fermentation of lactating cows.

Two experiments were conducted to examine the effect of zinc (Zn) source on the performance, Zn status, immune response, and rumen fermentation of lactating cows to find the most available Zn source for dairy production. In Experiment 1, a total of 30 multiparous Holstein cows were randomly allocated by body weight and milk yield to one of five treatments in a completely randomized design. Cows were fed a total mixed ration (TMR) with no Zn addition (containing 37.60 mg Zn/kg TMR by analysis), and the basal TMR supplemented with 40 mg Zn/kg TMR from either Zn sulfate or one of three organic Zn chelates with weak (Zn-AA W), moderate (Zn-Pro M), or strong (Zn-Pro S) chelation strengths, respectively for 55 days. In Experiment 2, the in vitro rumen fermentation method was used in a completely randomized design involving a 4 × 3 factorial arrangement of treatments. The four Zn sources were the same as those used in Experiment 1, and the three supplemental Zn levels in the rumen fluid were 0, 10, and 20 µg/mL, respectively. The feed intake, milk composition, and somatic cell count (SCC) were unaffected (P > 0.05) by treatments. However, the milk yield was increased (P < 0.05) by addition of Zn from both the Zn-AA W and Zn-Pro S. Plasma Zn level at the end of the experiment was increased (P < 0.05) by addition of Zn from all three organic sources. Serum antibody titers on day 21 after vaccination with foot and mouth disease (FMD) vaccine were increased (P < 0.05) by both supplemental Zn-AA W and Zn-Pro S. The organic Zn sources with different chelation strengths supplemented at the added Zn level of 10 µg/mL were more effective (P < 0.05) in improving the rumen fermentation than Zn sulfate, with the most effective being Zn-AA W. In conclusion, Zn source had no influence on the feed intake, milk composition, and SCC; however, both the Zn-AA W and Zn-Pro S were more effective than Zn-Pro M and Zn sulfate in enhancing the rumen fermentation, Zn status, and humoral immune response as well as improving milk yield of lactating cows. The improved milk production might be attributed to the improved rumen fermentation, Zn status, and immune function.

Effect of different levels of copper and molybdenum supplements on serum lipid profiles and antioxidant status in cashmere goats.

An experiment was conducted to investigate on the effects of different levels of copper (Cu: 0, 19, and 38 mg/kg) and molybdenum (Mo: 0 and 5 mg/kg) supplements and the interaction of these two factors on serum lipid profiles and antioxidant status in cashmere goats during the cashmere fiber growing period. Thirty-six Liaoning cashmere goats (approximately 1.5 years of age; 27.53±1.38 kg of body weight) were assigned to one of six treatments in a completely randomized design involving a 2×3 factorial arrangement. Goats were housed in individual pens and fed with Chinese wild rye- and alfalfa hay-based diet containing 4.72 mg Cu/kg, 0.16 mg Mo/kg, and 0.21 % S for 84 days. Blood samples were collected on day 84. The triglyceride concentration did not differ among treatments (P>0.05). Supplemental Cu, regardless of Mo level, decreased (P<0.05) the concentrations of serum total cholesterol and low density lipoprotein cholesterol, and increased (P<0.05) the concentration of serum high density lipoprotein cholesterol, but there were no differences (P>0.05) in these values between Cu-supplemented groups. Supplemental Cu increased (P<0.05) the activities of serum ceruloplasmin (Cp), Cu-zinc superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px), and decreased (P<0.05) the malondialdehyde content. The serum GSH-Px activity was also increased (P<0.05) by Mo supplementation. There was a tendency of the interaction effects of Cu and Mo on the activities of Cp (P=0.094), SOD (P=0.057), and GSH-Px (P=0.062), and goats fed with 19 mg Cu/kg in the absence of Mo tended to show the highest serum SOD activity, while goats fed with 38 mg Cu/kg with 5 mg Mo/kg tended to show the highest values of serum Cp and GSH-Px. Addition of Cu, Mo, or their interaction had no influence (P>0.05) on the activities of serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and lactate dehydrogenase, and the concentrations of serum glucose and total protein. In conclusion, addition of 19 mg Cu/kg in the absence of Mo (the total dietary Cu level of 23.72 mg/kg) was recommended for altering the fat metabolism and obtaining the optimal antioxidant activity of cashmere goats, while 38 mg Cu/kg should be supplemented when 5 mg Mo/kg was added in the basal diet (the total dietary level of 42.72 mg Cu/kg, 5.16 mg Mo/kg, and 0.21 % S) during the cashmere growing period.

Effect of different levels of copper and molybdenum supplements on performance, nutrient digestibility, and follicle characteristics in cashmere goats.

A 2 × 3 factorial arrangement of treatments was used to investigate the effects of different levels of copper (Cu, 0, 19, and 38 mg/kg, dry matter (DM)) and molybdenum (Mo, 0 and 5 mg/kg, DM) supplements and an interaction of these two factors on growth performance, nutrient digestibility, and cashmere and follicle characteristics in cashmere goats. Thirty-six Liaoning cashmere goats (approximately 1.5 years of age; 27.53 ± 1.38 kg of body weight) were assigned randomly to one of six treatments and fed with Chinese wildrye- and alfalfa hay-based treatment diets (the basal diet contained 4.72 mg Cu/kg, 1.65 mg Mo/kg, and 0.21% S.). Body weight was measured on two consecutive days at the start and the end of the 70-day experimental period. On day 30, the metabolism trial was conducted to study the effects of dietary Cu and Mo on nutrient digestibility. The cashmere and skin samples were collected on day 70. Copper supplementation increased (P < 0.05) growth performance and fiber digestion, but there were no differences (P > 0.05) between Cu-supplemented groups. Addition of 19 mg Cu/kg DM increased (P < 0.05) cashmere growth length or growth rate by increasing the number of active secondary follicles. Molybdenum supplementation decreased (P < 0.05) growth, but did not affect (P > 0.05) nutrient digestion, cashmere, and follicle characteristics. There is a tendency or significant interaction effect of Cu and Mo on growth performance (P = 0.057), cashmere growth (P = 0.076), or diameter (P < 0.05) which might be accomplished by changing the number of secondary follicle and active secondary follicle, and secondary to primary follicle ratio. In conclusion, the optimal supplemental Cu level for Liaoning cashmere goats fed with the basal diet was 19 mg/kg DM (the total dietary Cu level of 23.72 mg/kg DM), while 38 mg Cu/kg DM supplementation was found to be needed when 5 mg Mo/kg was added in the basal diet during the cashmere growing period.

Effect of dietary supplementation with copper sulfate or tribasic copper chloride on the growth performance, liver copper concentrations of broilers fed in floor pens, and stabilities of vitamin E and phytase in feeds.

An experiment was conducted using a total of 840, 1-day-old, Arbor Acres commercial male broilers to compare copper (Cu) sulfate and tribasic Cu chloride (TBCC, Cu(2)(OH)(3)Cl) as sources of supplemental Cu for broilers fed in floor pens. Chicks were randomly allotted to one of seven treatments for six replicate pens of 20 birds each, and were fed a basal corn-soybean meal diet (10.20 mg/kg Cu) supplemented with 0, 100, 150, or 200 mg/kg Cu from either Cu sulfate or TBCC for 21 days. Chicks fed 200 mg/kg Cu as TBCC had a higher (P < 0.05) average daily gain (ADG) than those consuming other diets. Liver Cu contents of broilers fed diets supplemented with TBCC were numerically lower (P > 0.05) than those of broilers fed diets supplemented with Cu sulfate. The vitamin E contents and the phytase activities in the feed fortified with TBCC were higher (P < 0.01) and numerically higher (P > 0.05) compared with those in the feeds fortified with Cu sulfate stored at room temperature, respectively. The vitamin E contents in liver and plasma of broilers fed diets supplemented with TBCC were higher (P < 0.05) than those of birds fed diets supplemented with Cu sulfate. This result indicates that TBCC is more effective than Cu sulfate in improving the growth of broilers fed in floor pens, and it is chemically less active than Cu sulfate in promoting the undesirable oxidation of vitamin E in feeds.