اثرات سطوح مختلف انرژی و پروتئین در گامه انتهایی آبستنی بر عملکرد، تولید پروتئین میکروبی، فراسنجه‌های خونی و شکمبه ای بزهای سیستانی

این پژوهش به‌منظور بررسی اثرات دو سطح انرژی و پروتئین خام پائین و بالا (به ترتیب مقادیر nrc (2007) و 10 درصد بالاتر از آن) در گامه سوم آبستنی بر وزن بدن، قابلیت هضم ظاهری، فعالیت نشخوار، فراسنجه های شکمبه ای، پروتئین میکروبی و وزن تولد بزغاله با استفاده از 28 راس بز سیستانی (وزن بدن 6/2±25 کیلوگرم، روزهای آبستنی 5±100) در قالب طرح کاملاً تصادفی با روش فاکتوریل 2×2 انجام شد. تیمارهای آزمایشی شامل: 1) پروتئین و انرژی پائین 2) پروتئین پائین و انرژی بالا 3) پروتئین پائین و انرژی بالا 4) پروتئین و انرژی بالا. ماده خشک مصرفی و کاهش وزن در زمان زایش در تیمار با پروتئین بالا انرژی پایین بیشتر بود. اما وزن تولد بزغاله این تیمار به طور معنی داری بالاتر بود. در فراسنجه های خونی 28 روز قبل زایش غلظت کلسترول در تیمار انرژی بالا پروتئین پایین به‌طور معنی داری افزایش یافت، اما غلظت‌های خونی گلوکز، تری گلیسرید، اوره و پروتئین کل تفاوت معنی داری نشان ندادند. در 14 روز قبل زایش، غلظت اوره خون در تیمار با پروتئین بالا به‌طور معنی داری بالاتر بود، اما تفاوت معنی‌داری در غلظت تری گلیسرید، کلسترول و پروتئین کل خون بین تیمارها وجود نداشت. در 2 ساعت بعد زایش تفاوت معنی داری در غلظت گلوکز و تری گلیسرید بین تیمارها وجود نداشت. تولید پروتئین میکروبی در تیمار با پروتئین بالا انرژی بالا بیشتر بود. تفاوت معنی داری در فراسنجه های شکمبه ای بین تیمارها مشاهده نشد. به‌طوری‌که ph مایع شکمبه قبل از مصرف خوراک در تیمار دارای انرژی بالا و پروتئین پایین نسبت به 3 ساعت بعد از مصرف خوراک بالاتر بود. همچنین غلظت اسیدهای چرب فرار شکمبه با مصرف جیره‌های حاوی انرژی بالا و پروتئین پایین‌تر از حد توصیه‌شده، افزایش یافت. به‌طورکلی نتایج نشان داد تامین نیاز انرژی و پروتئین در گامه انتهای آبستنی و افزایش سطح پروتئین موجب بهبود عملکرد و افزایش وزن تولد بزغاله در بزهای آبستن می شود.

Effect of Different of Levels Energy and Protein on Performance, Microbial Protein, Some of Metabolites and Ruminal Parameters in Late Pregnancy of Sistani Goat

Introduction[1]Nutrient requirements of goats have not been studied as extensively as those of beef and dairy cattle and sheep. Furthermore, Sistani goats have received less research attention than meat or dairy goats. Goats play an important role in Iran, largely as a source of red meat and milk. Iran has 25 million goats and kids. Results of research on ruminants showed that nutrients can affect prenatal growth if the lack of nutrition during gestation (in utero nutrition) will affect the postnatal growth performance. Dietary nutrient, especially energy and protein, are major factors affecting meat production in goats. During the late gestation, the last two months of pregnancy, eighty percent of the fetal growth occurs, leading to a significant increase in nutrient requirements of the ewe. Underfeeding energy or protein during pregnancy can lead to pregnancy toxemia, sub ketosis, or compromised fetal development, especially at the end of pregnancy when fetal growth rate is highest. The idea of using levels energy and protein in Sistani goat is new Therefore, this experiment conducted to test the effect energy and protein on on performance, digestibility, microbial protein, some of metabolites and ruminal parameters in late pregnancy of goat.  ;Materials and Methods The experiment was conducted in the Sari Agricultural Sciences and Natural Resources University (SANRU) of Iran. Humane animal care and handling procedures were followed according to the University’s animal care committee. On 100 days after successful matting, 28 synchronized singleton pregnant Sistani goats (with 3yearold; body weight = 25±1.6 kg, and body condition score =2.6±0.5) were randomly allocated to four treatments and fed with experimental rations including 1) low protein and low energy diets (LPLE), 2) high protein and low energy (HPLE), 3) low protein and high energy (LPHE), and 4) high protein and high energy (HPHE). Feeds and rations samples were dried at 55°C, ground through a Wiley mill (1mm screen), and composted by animal. Samples were analyzed for DM, OM, Kjeldahl N, ether extract (AOAC, 2002), ADF, NDF (Van Soest et al., 1991; using heat resistance alpha amylase without sodium sulphate), and ash at 605°C. The NFC was calculated by 100 (CP (%) + NDF (%) + Ash (%) + EE (%). The goats were weighted at the start of experiment, before and1 d after parturition, and Kids weight after birth. Nutrient digestibility, blood parameter, microbial protein synthesis and chewing activity. By measuring urine purine bases microbial protein synthesis was estimated. Rumination and chewing activity animal were measured visually with fiveminute intervals over 24 h for all animals. Rumen fluid was collected at o h before feeding and at 3h post feeding. The sample were sealed and placed in freezer before transport to the laboratory for the analysis the NH3 and VFA content.;Results and Discussion Our results showed that the intake of nutrients was increased in HPHE Treatment. Treatment HPLE had highest apparent digestibility than other experimental treatments. Goats on the higher CP diet lost more BW at parturition than other treatments. The lowest pH occurred at 3h post feeding. The ph of rumen fluid after the food ration is provided tends to decrease gradually because of fermentation in the rumen, particularly that of carbohydrates, which are degraded into VFA products. The VFA production increased at 3 h post feeding. There were no differences for microbial protein synthesis but had increase in treatment HPHE for microbial protein synthesis. Concentration of plasma cholesterol was significantly difference at 28d before generation. Glucose concentrations and urea were increased in HPLE treatments and Concentration of plasma triglycerid was lower in goats fed LPLE diet at 14d before generation. Glucose plasma concentration was higher in HPHE than other groups at 2h after generation. The birth live weight of kids was similar between the four groups but LPLE, LPHE and HPHE had numerically lower birth weight. The HPLE group had greatest and LPLE group had lowest body condition score.;Conclusion Overall, these results show that maternal protein feeding during late gestation has been positively associated with kid birth weight and performance. In this experiment, 10 % of CP concentration greater than NRC (2007) recommendation, increased the body weights kids and improved performance of goat. Although, it seems that further experiments are needed.