Studies On The Effects Of Glutamine On Weaning Stress And Energy Utilization Of Intestinal Epithelial Cells In Early-weaned Calves

The effects on energy utilization of intestinal epithelial cells, immune function, antioxidation function, intestinal mucous structure, muscle and intestinal mucous protein, DNA and RNA in early-weaned calves by infusing glutamine were studied in this thesis, which implements for manipulation of weaning stress in early-weaned calves.There are three parts in this study.Part 1 .Studies on the weaning stress status in early-weaned calves.Three Chinese Holstein calves with similar weight and date of birth were selected and weaned at 40±1d to study the effects of weaning stress on plasma glutamine, immune function, antioxidation function, intestinal absorption function, nitrogen deposition and blood biochemical index. The results indicated that the content of plasma glutamine , immune and antioxidation function .feed intake, intestinal absorption function, nitrogen deposition, plasma glucose were decreased significantly ,plasma growth hormone and insulin were decreased significantly, and plasma urine nitrogen andβ-hydroxybutyric acid were increased significantly. Glucagons was increased too.Part 2. Studies on the energy utilization of intestinal epithelial cells in early-weaned calves.Three Chinese Holstein calves with similar weight and date of birth were selected and weaned at 40±1d.These calves were slaughtered at 2d after weaning, then intestine was taken out and jejunum was separated under asepsis conditions. The intestinal epithelial cells were cultured in vitro by adding different levels of glutamine and glucose in DMEM culture medium. The results indicated that adding duple glutamine of plasma glutamine level was beneficial to the attachment and growth, secretion and energy reservation of intestinal epithelial cells.Part 3 Studies on the manipulation of weaning stress by infusing glutamine in early-weaned calves.Twelve Chinese Holstein calves with similar weight and date of birth were selected and divided randomly into four groups. They were weaned at 40±1d. Alanyl-glutamine peptide (Ala-Gin) was supplemented through jugular vein by total parenteral nutrition (TPN). The objection of this part was to study the effects of different infusing glutamine levels on immune, antioxidation function and other functions in early-weaned calves. Ala-Gin levels were designed as follows: trial I (control group, 0g/kg BW/d ), trail II (low-Gin group, 0.34g/kg BW/d), trail III (mid-Gin group, 0.68 g/kg BW/d), trail IV (high-Gin group, 1.36 g/kg BW/d), and the injection lasted for 7d continuously. The results indicated that : (1) the daily gain was increased significantly and feed intake, feed utilization efficiency , nitrogen deposition and protein synthesis were increased, but the rates of diarrhea were decreased by infusing medium Ala-Gin levels through total parenteral nutrition (TPN) in early-weaned calves. (2) the immune and antioxidation function were improved by infusing medium Ala-Gin levels through total parenteral nutrition (TPN) in early-weaned calves.(3)the intestinal villus height and mucous thickness were increased, but recess depth was decreased. At the same time, the levels of muscle protein, jejunum mucous DNA concentration and RNA concentration in jejunum mucous and muscle were improved by infusing medium Ala-Gin levels through total parenteral nutrition (TPN) in early-weaned calves.