اثر جيره¬هاي گلوكوژنيك و ليپوژنيك بر غلظت زيست نشانگرهاي انرژي در سرم خون بره‌هاي ماده بلوچي

The Effect of Glucogenic and Lipogenic Diets on Blood Serum Concentration of Energy Biomarkers in Female Baloochi Lambs

تعداد بیست و هشت رأس بره ماده بلوچی با میانگین سن 3/2 ± 9/14 هفته و وزن 6/4 ± 3/26 كیلوگرم از جیره‌های با یا بدون پیه، بر پایه دانه ذرت یا جو، در قالب طرح كاملا تصادفی به روش فاكتوریل 2×2 به مدت 9 هفته تغذیه شدند. مصرف جیره‌های آزمایشی اثری بر میانگین خوراك مصرفی بره‌ها نداشت، اگرچه افزایش وزن روزانه و بازدهی خوراك در هفته‌های 4 تا 8، تحت تأثیر اثر تداخل چربی × غله قرار گرفت و در تیمار لیپوژنیك-ذرت بالاترین مقدار بود. افزودن پیه به جیره، به ترتیب سبب افزایش و كاهش غلظت كلسترول و گلوكز سرم بره‌ها در طول دوره آزمایش شد. درحالی‌كه، غلظت انسولین و نسبت گلوكز: انسولین، تحت تأثیر اثر غله قرار گرفته، در تیمارهای جو در مقایسه با ذرت، به ترتیب افزایش و كاهش یافت. در بره‌های تغذیه شده با جیره‌های لیپوژنیك در مقایسه با جیره‌های گلوكوژنیك، غلظت پایه گلوكز كاهش و غلظت پایه كلسترول و آسپارتات آمینوترانسفراز افزایش یافت. ازطرفی، غلظت پایه اسیدهای چرب استریفیه نشده سرم و شاخص كمی حساسیت انسولینی تحت تأثیر اثر تداخل چربی × غله قرار گرفته و شاخص حساسیت انسولینی به طور معنی‌دار با بازدهی خوراك همبستگی مثبت نشان داد. به نظر می رسد غلظت چربی و كمیت و ماهیت منبع نشاسته‌ای جیره، عواملی هستند كه می‌توانند بر فراسنجه‌های حساسیت انسولینی نشخواركنندگان اثرگذار باشند. همچنین، به نظر می‌رسد جیره‌هایی كه نسبت مطلوبی از چربی و نشاسته را فراهم كنند، بتوانند سبب بهبود بازدهی و وضعیت انرژی حیوان شوند.

Introduction Recently, dietary balance of glucogenic and lipogenic nutrients is known as an important factor on severity of the NEB and metabolic disorders in transition dairy ruminants. Insulin plays a central role in metabolism by stimulating utilization of glucose in peripheral tissues such as muscle and adipose tissue and by promoting accumulation of glycogen and lipid reserves. In this study the main hypothesis was that plasma insulin concentration would be influenced by dietary quantity and quality of starch and fat. In different studies in dairy cows, insulin was increased by diets with high starch content and was decreased by diets with high fat content, although increased insulin concentrations were found when supplementary fat increased energy intake. Blood concentrations of NEFA, BHBA, Glucose, insulin, cholesterol, AST and the quantity of RQUICKI were assigned to detect the insulin sensitivity in dairy cows. This experiment was aimed to study the dietary fat concentration and starch degradability effects on insulin resistance in ruminants in equal energy diet, using Baluchi sheep. Materials and methods Twenty and eight female Baluchi lamb with 14.9 ± 2.3 wk of age and 26.3 ± 4.6 kg of BW were assigned to 4 treatments in completely randomized design with 2×2 factorial arrangement and fed 4 rations; 1) without tallow-corn (glucogenic-corn), 2) without tallow-barley (glucogenic-barley), 3) tallow-corn (lipogenic-corn) and 4) tallow-barley (lipogenic-barley), for 9 weeks. Experimental TMR rations were formulated with 60% concentrate and 40% alfalfa according to the AFRC, 1993. Lambs had free access to clean water and feed through individual boxes. Daily feed intake, body weight gain and fasting blood sampling were detected weekly. Blood sampling were sampled by the 6ml tubes (Gel/Clot activator, GD060SGC, Zhejiang Gongdong Medical Technology Co., Ltd), then Serums were reserved in the -800C until blood metabolites detection. Statistical analysis was performed by SAS (9.1) software. Results and discussion Experimental diets was not affected on average feed intake of lambs, but body weight gain and feed efficiency in week 4 to 8, affected by fat × cereal interaction and they were highest in lipogenic-corn treatment and feed efficiency was correlated with serum glucose concentration (P <0.05). Glucogenic diet may increase the tissue retention by increasing the glucose and insulin blood concentration in the cow. Blood insulin was higher in barley vs. corn diet (P <0.05). Injection of propionate more than glucose or butyrate increased blood insulin in lamb. So, by feeding the barley diet it may be degraded more starch in the rumen and increase the amount of propionate blood concentration which stimulated more insulin secretion. Supplementing tallow in a diet increased cholesterol and AST, but decreased glucose concentration in this experiment (P <0.05), although the amount of them were in normal range. It would be indicated the lipogenic diet could be disposed lambs to the fatty liver diseases. In other hand, basal concentration of serum non esterified fatty acids and Revised Quantitative Insulin Sensitivity Check Index (RQUICKI) affected by fat × cereal interaction and RQUICKI was positively correlated with feed efficiency (P <0.05). It seems that there was no correlation between RQUICKI and metabolically disorders in ruminants however the RQUICKI is a good factor for evaluation of feed efficiency in ruminant nourishment. Conclusion Fat concentration, quantity and quality of starch source in a diet are parameters that may affect insulin sensitivity metabolites in ruminants. It seems that when moderate levels of fat and starch coincides in ruminant diet, their efficiency and energy status can improve.