تاثیر مکمل های آلی و معدنی روی در جیره بره های نر نژاد کرمانی بر غلظت مواد معدنی، وضعیت آنتی اکسیدانی و برخی فراسنجه های خون

به منظور بررسی اثر تغذیه مکمل های رویمتیونین و سولفات روی بر غلظت مواد معدنی و برخی فراسنجه های خون بره های نر کرمانی، 21 راس بره 7 ماهه با متوسط وزنی 0.90± 28 کیلوگرم انتخاب و جیره های شاهد (فاقد مکمل روی)، روی متیونین (40 میلی گرم در کیلوگرم ماده خشک) و سولفات روی (40 میلی گرم در کیلوگرم ماده خشک) در قالب یک طرح کاملا تصادفی با 3 تیمار و 7 تکرار به مدت 9 هفته بر روی بره ها اعمال شد. خون گیری در شروع (زمان صفر) و هفته های 3، 6 و 9 آزمایش انجام شد. غلظت کلسیم و فسفر سرم در طی زمان افزایش یافت (p<0/05) اما بین گروه های آزمایشی تفاوتی وجود نداشت. یافته های این آزمایش نشان داد که غلظت روی سرم بره ها قبل از شروع آزمایش کمتر از حد نرمال (90-150 میکروگرم در دسی لیتر) بود، اما در طی آزمایش افزایش یافت. میانگین غلظت روی سرم خون در گروه های تغذیه شده با مکمل های آلی و معدنی روی به طور معنی داری بالاتر از گروه شاهد بود (p<0/05) و این تفاوت بیشتر در هفته سوم آزمایش مشهود بود. غلظت مس، گلوکز و پروتئین تام سرم تحت تاثیر تیمارهای آزمایشی قرار نگرفت. اما در طی زمان، غلظت گلوکز و پروتئین تام افزایش یافت (p<0/01). میانگین فعالیت آنزیم سوپراکسید دیسموتاز در گروه رویمتیونین بیشتر از شاهد بود ( p<0/05). فعالیت آنزیم آلکالین فسفاتاز، مشابه با تغییرات روی، در بره های تغذیه شده با مکمل های روی در هفته 3 آزمایش بالاتر بود (p<0/05). نتایج این آزمایش نشان داد که استفاده از مکمل های رویمتیونین و سولفات روی به میزان 40 میلی گرم در کیلوگرم خوراک بره های نر تغذیه شده با جیره پایه حاوی 48 میلی گرم روی و 11.7 میلی گرم مس در هر کیلوگرم ماده خشک، سبب افزایش غلظت روی سرم خون و فعالیت آنزیم های سوپراکسید دیسموتاز و آلکالین فسفاتاز شد و بر غلظت سرمی کلسیم، فسفر، مس، گلوکز و پروتئین تام اثر منفی نداشت. همچنین تفاوتی بین اثرات دو مکمل آلی و معدنی روی بر فراسنجه های یاد شده مشاهده نشد.

Dietary organic and inorganic zinc supplements in Kermani male lambs: Impacts on serum minerals, antioxidant status and some blood parameters

Introduction:;Sheep production in arid and semiarid parts of Iran undergoes feed shortage due to poor natural vegetation. Trace minerals, as metabolic modifiers, are essential in ruminants’ diets because of their contribution in biochemical processes required for normal growth and development. Zinc (Zn) is one of the most deficient minerals in soils of many parts of the world including Iran. Zinc is known to affect growth, reproduction and immune system of the animals. Although administration of Zn supplements in ruminants’ diets has been receiving increased attention in recent years, however, it is not wellestablished that how much of Zn supplement is more effective for improving fattening lambs’ performance, metabolism and antioxidant status. Furthermore, there are a few information about blood minerals of Kermani sheep. Thus, the aim of this study was to evaluate the likely effects of different Zn sources on some blood parameters related to animal health and production.;Materials and Methods:;This study was conducted at the Research Station of Department of Animal Sciences, University of Jiroft, Iran. Twentyone Kermani male lambs (7 months of age, 28 ± 0.9 kg of body weight) were assigned to 1 of 3 following treatments (7 lambs each) for 9 weeks in a completely randomized design: (1) Control diet; (2) Control diet plus supplemental zincmethionine (ZnMet, 40 mg/kg dry matter (DM)) and (3) Control diet plus supplemental zinc sulfate (ZnSO4, 40 mg/kg DM). Two weeks adaptation period to basal diet was done before the experimental period. Basal diet contained 48 and 11.7 mg/kg DM of Zn and Cu respectively. Blood samples were collected before commencement (time 0), and at weeks 3, 6 and 9 of the experiment. Serum minerals and metabolites concentrations and whole blood superoxide dismutase activity (SOD) were measured. Maximum air temperature and minimum relative humidity data were used to calculate the temperaturehumidity index (THI). Statistical analysis was carried out using SAS software. A mixed model with fixed effects of treatment, week and treatment × week, as well as the random effect of lamb within treatment × week were used. Time of sampling (week) was used as a repeated effect and subject for the repeated statement was lamb within dietary treatment. Where biologically worthwhile and significant, the initial values for blood metabolites (before supplementation (time 0)) and initial body weight were included in model as a covariate to further improve the analysis precision. The significant differences were declared and tendencies .;Results and Discussion:; Based on the findings, Kermani male lambs of this study had deficient blood Zn contents (under 90 µg dl1) before the commencement of the experiment. Lambs on ZnMet and ZnSO4 supplemented diets had higher serum average Zn concentrations than those on the control diet (P &lt;0.05). Serum Zn content showed a timedependent trend so that Znsupplemented groups had higher Zn concentrations at week 3 in spite of weeks 6 and 9 of the experiment (P &lt;0.05). The concentrations of serum calcium, phosphorous and copper were not affected by the treatments. However, calcium and phosphorous increased by time (P=0.02). Dietary Zn supplementation of lambs, irrespective of its source, led to increased average blood alkaline phosphatase activity (ALP) which was more obvious in week 3 of the experiment (P &lt;0.05). This similar trend between Zn and ALP contents through time may imply to the close association between blood Zn concentration with ALP activity. Lambs on ZnMetsupplemented diet exhibited improved SOD activity comparing those on the control diet (P &lt;0.05). These findings, suggesting that at least the supplemented Zn is being incorporated in the system, resulting in increased SOD activity. Serum glucose and total protein concentrations increased during time (P &lt;0.01) but no differences were observed among experimental groups.;Conclusion:; These results indicated the beneficial effects of dietary Zn supplementation of 40 mg/kg diet for increasing serum Zn concentration and alkaline phosphatase activity of male lambs. ZnMet was more effective than ZnSO4 for improving antioxidant status. In addition, no adverse effects of Zn supplementation on serum copper, calcium, phosphorous, glucose and total protein concentrations were observed. Additionally, some blood parameters such as Zn concentration and ALP activity revealed a timedependent variation in this study which suggests that repeated blood sampling may be more appropriate than endpoint sampling particularly in respect to blood metabolites.