فهرست مقالات residual feed intake

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  1 - Growth Performance, Rumen and Cecum Fermentation Parameters, and Microbial Protein Synthesis in Kermani Lambs with Divergent Residual Feed Intake Fed Forage and Concentrate Diets
  M. Gevari M.R. Dehghani M. Yousef Elahi R. Hoshyar
  < p style="text-align: justify;">It was hypothesized that some of the variations in rumen and cecum fermentation parameters can form a share of individual differences resulting in feed efficiency, which may be altered based on the type of diet. This research aimed چکیده کامل

  < p style="text-align: justify;">It was hypothesized that some of the variations in rumen and cecum fermentation parameters can form a share of individual differences resulting in feed efficiency, which may be altered based on the type of diet. This research aimed to determine the effects of dietary effect and feed efficiency of growing lambs (Kermani lambs) on their rumen and cecum indices and also microbial protein synthesis in gastrointestinal tract. Lambs (n=40; bodyweight (BW)=16±1.5 kg) were fed either a concentrate (CONC; 11.8% crude protein (CP), 18% neutral detergent fiber (NDF), 2.66 Mcal/kg metabolizable energy (ME); n=20) or a forage-based diet (FOR; 15.6% CP, 36.8% NDF, 2.15 Mcal/kg ME; n=20). Individual intake was recorded and residual feed intake (RFI) was determined over 42 days. The 8 highest (Low-RFI) and 8 lowest efficiencies (High RFI) records of lambs from each dietary group were selected (n=16; average BW=20±2.1 kg), and the samples of rumen and cecum fluid, and also urine were collected at the end of the trial. Data were analyzed as a 2 × 2 factorial design with RFI class (high vs. low efficiency), their type of diet (FOR vs. CONC), and their interaction in the defined model. Based on the results, high-efficiency lambs had a higher level (p < 0.01) of total volatile fatty acid (VFA), proportional concentrations of acetate, propionate, and ammonia nitrogen in the rumen in comparison to low-efficiency lambs. Higher (p < 0.01) amounts of allantoin, xanthine + hypoxanthine, total purine derivative (PD), microbial nitrogen and microbial protein were observed in the high efficiency than low-efficiency lambs. The low efficiency lambs had greater (p < 0.01) proportional acetate, cecal pH and cecal ammonia N compared to high-efficiency lambs. The RFI class × diet type interaction was significant (p < 0.01) for the majority of parameters of the rumen, cecum, and microbial protein synthesis. The results of this experiment exhibited that hindgut fermentation especially cecum played a key role in the efficiency of feed utilization in lambs which have consumed larger amounts of fermentable substrates. پرونده مقاله
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  2 - Effect of Different Fat Sources on some Blood Metabolites, Hormones, and Enzyme Activities of Lambs with Different Residual Feed Intake in Heat-Stressed Condition
  G. Halakoo ا. تیموری یانسری M. Mohajer Y. Chashnidel
  Most efficient animals in heat-stressed condition, intelligently regulate their metabolism for maximizing their productivity and fats play an important role in reducing heat stress in these animals but the underlying mechanisms remain elusive. The effects of different f چکیده کامل

  Most efficient animals in heat-stressed condition, intelligently regulate their metabolism for maximizing their productivity and fats play an important role in reducing heat stress in these animals but the underlying mechanisms remain elusive. The effects of different fat sources on some blood metabolites and hormones and enzyme activities of heat-stressed lambs with different residual feed intake (RFI) were studied. In the preliminary trial, 48 male lambs of four different breeds (Zel, Dalagh, and their hybrids with Romanov; BW=16.87±0.55 kg) in a block randomized complete design used to assay RFI for 67 days. After that, 32 lambs of the same breeds as a block (BW=30.74±1.21 kg) with two different RFIs in heat stressed condition were used in a 2 × 4 factorial trail over 84 days. The treatments included four rations: 1) basal ration (control), 2, 3, and 4) rations supplemented with calcium soap fatty acids (FA), beef tallow, and canola oil, respectively. Dry matter intake (DMI) was high in control and high RFI groups (low efficient) (p < 0.05). Lipid sources had significant effect on serum glucose, cholesterol, triiodothyronine (T3), and Insulin, pulse and respiration rate (p < 0.05). No differences found between treatments for triglyceride, thyroxine(T4), low-density lipoprotein (LDL), and Very-low-density lipoprotein (VLDL). Glucose concentration had strong correlation with the RFI (p < 0.01). The Low RFI lambs (LRFI) had high T3 and low LDH levels. These lambs had high respiration and pulse rate (p < 0.05). Lambs fed with fat supplemented rations had higher concentration of serum aspartate aminotransferase (AST), alkaline phosphatase (ALP), and lactic dehydrogenase (LDH) enzymes than control (p < 0.01). Lipid supplementation in heat stressed lambs markedly alters glucose, cholesterol, T3 and respiration and pulse rate that independently of reduced dry matter intake (DMI) through coordinated changes in fuel supply and utilization by multiple tissues. Even more challenging the most efficient lambs (LRFI) had high physiologic rate and high activity for removing heat from tissues. پرونده مقاله