اثر تزریق سطوح مختلف ویتامین A قبل از جفت‌گیری بر عملکرد تولیدمثلی میش‌های افشاری

نوع مقاله : مقاله پژوهشی

نویسندگان

• فرشته عسگری ¹
• محمد شمس الهی ²
• فرشید فتاح نیا ¹
• محمد اکبری قرائی ²
• شهناز یوسفی زاده ³

¹ گروه علوم دامی، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران.

² گروه علوم دامی، دانشکده کشاورزی، دانشگاه ایلام، ایلام، ایران

³ گروه علوم آزمایشگاهی و بالینی، دانشکده پیراپزشکی، دانشگاه ایلام، ایلام، ایران

چکیده

کلیدواژه‌ها

• میش افشاری
• جفتگیری
• ویتامین A
• وضعیت آنتی‌اکسیدانی
• عملکرد تولید‌مثلی

موضوعات

• فیزیولوژی دام

عنوان مقاله [English]

The effects of replacement of forage source with date palm leaves based on undigested neutral detergent fiber on performance of feedlot lambs Effect of different levels of vitamin A injection before mating on reproductive performance of Afshari ewes

نویسندگان [English]

• Fereshteh Asgari ¹
• mohammad shamsollahi ²
• farshid fatahnia ¹
• mohammad Akbari Qaraei ²
• Shahnaz Yousefizadeh ³

کلیدواژه‌ها [English]

• Afshari ewes
• Mating
• Vitamin A
• Antioxidant status
• Reproductive performance

Extended Abstract

Introduction

     Meat production is the main purpose of sheep production in Iran. Efficiency of reproductive performance and the number of lambs born are main factors affecting meat yield in sheep production industry. Most Iranian sheep breeds have seasonal reproduction, they usually give birth to one lamb at each birth, and therefore their profitability is low. Sheep reproductive performance is affected by many factors including the length of reproductive season, ovulation rate, pregnancy rate, number of lamb born and offspring survival. All of these factors are influenced by the interaction of genetics and environmental factors. Nutrition is one of the most important environmental factors affecting reproduction performance of ruminant animals from the beginning of puberty to the total number of offspring born during their lifetime. Oxidative stress is the result of an imbalance between production of free radicals and antioxidants status. Free radicals can affect many reproductive events such as cell cycle activation, ovulation and luteolysis. Excessive production of free radicals surpasses antioxidant capacity, increased oxidative damage and reduced reproductive performance. Antioxidants supplementation prevents oxidative damage and can be an ideal strategy to improve fertility in females. The most known antioxidants are vitamins such as vitamins A, C, E, beta-carotene and some trace minerals. Vitamin A is well known to regulate cellular growth and differentiation, ovarian follicular growth, uterine environments and oocyte maturation. Vitamin A deficiency has a direct effect on the structure and function of pituitary gland, gonads and uterus. To our knowledge, the effects of vitamin A injection around mating on reproductive performance and metabolic status of ewes have not been well investigated. We hypothesized that injection of a solution containing vitamin A around mating would increase reproductive performance of ewes. Therefore, the objective of the present study was to evaluate the effect of vitamin A injection before mating on plasma parameters, antioxidant status and reproductive performance of Afshari ewes.

Materials and Methods

    This study was conducted in a commercial farm (Ilam, Iran) during the breeding season (June-December). Seventy-five Afshari ewes were randomly allocated into three groups (n = 25) based on age (3.6±0.9 years) and BW (43.5±4.2 kg). One month before the beginning of experiment, all ewes were vaccinated against clostridial diseases (Razi Institute, Hesarak, karaj, Iran) and treated with anthelmintic drugs against external and internal parasites (Ivermectin, subcutaneous injection, 0.2 mg/kg BW; Hepatec 500, bolus, 5 mg/kg BW; and Niclosam 1250, bolus, 62 mg/kg BW; Damloran Pharmaceutical Co., Borujerd, Iran). The experimental treatments included 1- control ewes (without vitamin A injection), 2 - ewes receiving 0.25 ml of vitamin A and 3- ewes receiving 0.5 ml of vitamin A. Each mL of solution contained 100,000 IU of vitamin A as retinol palmitate and was injected intramuscularly on the day of sponge insertion and sponge removal. Body condition score (BCS), plasma metabolites and antioxidant status were measured at the beginning of the experiment, the day of sponge removal and the day of estrus. All animals were fed the same flushing diet twice daily (09:00 and 18:00) as a total mixed ration (TMR). Animals had free access to water throughout the experiment. At the end of feeding flushing diet all ewes managed as a single group and kept in similar management and feeding condition throughout pregnancy and lambing.

Results and Discussion

    The results showed that injection of 0.5 ml of vitamin A before mating increased glucose concentration on the day of estrus compared to other treatments (P<0.05). Ewes received 0.25 mL of vitamin A had lower plasma cholesterol concentration at the day of estrus compared to other groups (P < 0.05). Higher antioxidant capacity at the day of sponge removal was observed in ewes received 0.5 mL of vitamin A than other treatments (P<0.05). Plasma malondialdehyde concentration on the day of sponge removal and the day of estrus was significantly reduced by injection of 0.25 and 0.5 ml of vitamin A compared to the control treatment (P<0.05). Lambing rate, fertility rate and twinning rate did not influence by injection of 0.25 or 0.5 ml of vitamin A before mating (P< 0.05).

Conclusion

 In general, injection of different level of vitamin A before mating, despite improving antioxidant capacity, had no significant effect on reproductive performance of Afshari ewes.

Author Contributions

 All authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.

Data Availability Statement

 Data available on request from the authors.

Acknowledgements

 The authors would like to thank all participants of the present study.