Effects of small peptides or amino acids infused to a perfused area of the skin of Angora goats on mohair growth

Effects of soybean small peptides on rumen fermentation and on intestinal and total tract digestion of luxi yellow cattle

Four Luxi beef cattle (400±10 kg) fitted with ruminal, duodenal and ileal cannulas were used in a 4×4 Latin square to assess the effects of soybean small peptide (SSP) infusion on rumen fermentation, diet digestion and flow of nutrient in the gastrointestinal tract. The ruminal infusion of SSP was 0 (control), 100, 200 and 300 g/d. Ruminal SSP infusion linearly (p<0.01) and quadratically (p<0.01) increased microbial protein synthesis and rumen ammonia-N concentration. Concentrations of total volatile fatty acid were linearly increased (p = 0.029) by infusion SSP. Rumen samples were obtained for analysis of microbial ecology by real-time PCR. Populations of rumen Butyrivibrio fibrisolvens, Streptococcus bovis, Ciliate protozoa, Ruminococcus flavefaciens, and Prevotella ruminicola were expressed as a proportion of total Rumen bacterial 16S ribosomal deoxyribonucleic acid (rDNA). Butyrivibrio fibrisolvens populations which related to total bacterial 16S rDNA were increased (p<0.05), while Streptococcus bovis populations were linearly (p = 0.049) and quadratically (p = 0.020) decreased by infusion of SSP. Apparent rumen digestibility of DM and NDF were (Q, p<0.05; L, p<0.05) increased with infusion SSP. Total tract digestion of DM, OM and NDF were linearly (p<0.01) and quadratically (p<0.01) increased by infusing SSP. The flow of total amino acids (AA), essential amino acids (EAA) and individual amino acids were linearly (p<0.01) and quadratically (p<0.01) increased with infusion SSP. The digestibility of Lysine was quadratically (p = 0.033) increased and apparent degradability of Arginine was linearly (p = 0.032) and quadratically (p = 0.042) increased with infusion SSP. The results indicated that infusion SSP could improve nutrient digestion, ruminal fermentation and AA availability.

Effects of prolactin administered to a perfused area of the skin of Angora goats

It is suspected that prolactin may affect mohair growth; therefore, effects of infusing prolactin on mohair growth were investigated using a skin perfusion technique. Seven Angora wethers (average body weight, 30 +/- 3 kg) were implanted bilaterally with silicon catheters into the superficial branches of the deep circumflex iliac artery and vein. For the first 14 d of the experiment, animals were infused (2.4 mL/h) with prolactin (one side) or control (other side) into the deep circumflex iliac arteries. The infusion rate of prolactin was 2.21 mg/d and was calculated to triple prolactin blood concentration in the perfused region. The area of skin supplied by the deep circumflex iliac artery was approximately 240 cm2. Two weeks after the cessation of infusions, 100-cm2 areas within the perfused regions were shorn to determine mohair growth. Greasy and clean mohair production was decreased (P < 0.05) by prolactin compared with control (3.79 vs 4.62 and 3.02 vs 3.67 g/[100 cm2 x 28 d], respectively). Oxygen satura tion in blood hemoglobin from the deep circumflex iliac veins was greater (P < 0.02) on the side infused with prolactin than on the control side (75.1 vs 68.2%). Higher concentrations of methionine, lysine, valine, isoleucine, and leucine were observed in blood of the deep circumflex iliac vein on the side infused with prolactin vs that infused with control (P < 0.05). In conclusion, direct skin infusion with prolactin decreased mohair fiber synthesis by the skin and may have concomitantly lessened oxygen consumption. Thus, effects of increasing prolactin concentration approximately two-fold in the skin on mohair fiber growth may not be limited to simple competition for nutrients between skin and other tissues such as the mammary gland.