تأثیر سطوح مختلف نانواکسید مس و سولفات مس بر عملکرد، ایمنی، فراسنجه‌های خونی و خصوصیات لاشه بره‌های پرواری

Introduction: Recently, nanoparticles have been produced and marketed using nanotechnology. Reducing the size of particles to nanoparticles (size less than 100 nm) increases the surface-to-volume ratio and changes other material properties. Increasing the contact surface in nanoparticles causes their interaction with organic and inorganic molecules to be done differently. Among the minerals, copper is an essential, scarce element that performs various functions in living organisms. It has been reported that copper nanoparticles have beneficial effects on animal performance and can replace copper sulfate. Also, nano copper oxide has several advantages over copper sulfate, including improved effectiveness, lower dosage with better results, no interference with other materials, and less disposal in the environment, and can replace copper sulfate. High copper in the diet has benefits such as antibacterial activity, increasing growth hormone secretion, increasing feed intake and production performance. However, environmental pollution and subsequent accumulation in feed and water can affect vital organs such as the liver and kidney.
The objective of this study was to investigate the effect of different copper forms and levels (copper nano oxide and copper sulfate) on performance, blood parameters and immunity in Romanov-Moghani crossbred lambs.
Materials and methods: This research was conducted using 30 lambs in the form of a completely randomized design with 5 experimental groups and 6 replications (lambs) in each group. The duration of the experiment was 56 days. The experimental diets of this research include: 1) basal or control diet (CON; without copper supplementation), 2) basal diet + 10 mg of copper per kg of dry matter in the form of copper sulfate (CuS10), 3) basal diet + 20 mg of copper per kg of dry matter in the form of copper sulfate (CuS20), 4) basal diet + 10 mg of copper per kg of dry matter in the form of copper nano oxide (CuN10), 5) basal diet + 20 mg of copper per kg of dry matter in the form of copper nano oxide (CuN20). Lambs were randomly grouped based on body weight and each group was fed with one of 5 experimental diets. On the 30th and 56th days of the experimental period, blood samples were collected from the jugular vein 3 hours after the morning meal. Next, after separating serum and plasma, the samples were kept at -20◦C until the analysis. The determined blood parameters include the concentration of copper, zinc, selenium, malondialdehyde, glucose, cholesterol, triglyceride, total protein, albumin, urea, beta-hydroxybutyrate, liver enzymes (ALT and AST). Total antioxidant capacity, activity of glutathione peroxidase, superoxide dismutase and catalase enzymes were also determined.
After killing the animals, meat samples were taken from the 12-13 intercostal eye muscle to determine the concentration of copper, zinc and selenium elements, and liver samples were also taken. Liver, meat and blood samples were digested by the method of Kechoui et al. (2013). For the analysis of blood and tissue samples, ICP-OES (model: Optimum 7300 DV) was used at Isfahan University. At the time of animal slaughter, the quantitative and qualitative characteristics of the carcass, including the weight of the heart, kidney, lungs, liver, and tail, along with the cold carcass and the hot carcass, were recorded. The resulting data were analyzed in the form of a completely randomized design using SAS software (2003). Means were shown as Least Squares (LSMEAN) along with standard error and mean comparisons at a significance level of five percent.
Results and discussion: The results of this study showed that the use of copper sulfate and copper nano oxide at the levels of 10 or 20 mg/kg dry matter of the diet had no significant effect on the performance parameters of fattening lambs, in terms of body weight, live weight gain, dry matter intake and feed conversion ratio (P>0.05). Also, the findings of this research showed that the concentration of blood urea in 30 days increased significantly with CuS10 and CuN10 treatments (P<0.05). Other blood parameters such as glucose, cholesterol, triglyceride, albumin, protein, BHBA, AST, ALT enzymes and antioxidant indices superoxide dismutase, glutathione peroxidase and total antioxidant capacity were not affected by the experimental treatments (P>0.05). The supplemental feeding of nano copper oxide increased catalase enzyme activity in blood samples (P<0.05). Copper concentration was increased in the liver significantly as a result of feeding 20 mg of copper in the form of copper nano oxide(P<0.05). Supplemental feeding of copper sulfate decreased the concentration of selenium in meat compared to the control group (P<0.05). Carcass characteristics including the percentage of hot carcass and cold along with the percentage of internal organs (tail, heart, liver, kidney and lungs) were not significantly different among the treatment groups (P>0.05).
Conclusion:
According to the present results, the use of mineral and nano forms of copper at levels of 10 or 20 mg/kg dry matter of the diet had a significant effect on parameters such as blood urea, malondialdehyde, catalase enzyme activity, percentage of copper in blood and selenium in meat. However, no significant difference was observed in performance and most blood parameters, antioxidant indices, total antioxidant capacity, activity of superoxide dismutase, glutathione peroxidase enzymes, carcass characteristics of fattening lambs and clinical signs of poisoning in lambs of treatment groups. This shows that the levels used in this study did not have the potential of poisoning and health risks for the tested lambs. Considering the improvement of liver concentrations of copper in the treatment receiving copper nano oxide source; it seems that the use of 20 mg/kg of dry matter of copper nano oxide can be a useful strategy in reducing the disposal of this element and reducing environmental pollution.