Submitted to: Journal of Animal Science Supplement
Publication Type: Abstract Only
Publication Acceptance Date: 7/31/1998
Publication Date: N/A
Technical Abstract: The addition of spray-dried plasma protein (PP) to early growing pig diets results in increased food intake and faster growth. The physiological mechanisms affected by PP are not known. At 14 d of age, 26 barrows were fitted with gastric cannuli and randomly assigned within a 2x3 factorial experimental design, including treatments of PP or no PP and feeding levels sof 80%, 100%, or 120% of normal feed intake. Pigs were fed through gastri cannuli every 2 hr from 10 a.m. to 10 p.m. for 11 d, then sacrificed for tissue collection. Blood samples were drawn on d 2,5,8, and 11, and body weight (BW) was recorded daily. RNA expression was quantified by hybridization assays and serum IGF-1 concentrations were measured by radioimmunoassay. Data were analyzed by two-way ANOVA (with repeated measures where appropriate). An effect of feeding level was found in BW through time (P=.037), d 11 BW (P=.003), and ADG (P<.001). All of these endpoints were lower in the 80% feed intake groups than in the 100% or 120 feed intake groups. The slopes of the growth curves also differed by level (80%<100%<120%, P<.001). No effect of plasma on weight gain was observed. Leptin, adipose IGF-1 and liver IGF-1 RNA expression did not differ between level or plasma. Serum IGF-1 concentrations were correlated with ADG across treatments (R=.579, P=.002), as was adipose IGF-1 RNA expression with ADG (R=.482, P=.015). Leptin RNA expression was correlated with ADG only at the 100% feeding level (R=.677, P=.045). The only endpoint measured which showed significant differences due to PP was hypothalamic IGF-1 RNA expression (decreased in PP-treated pigs, P=.032). These data suggest that, when feed intake is controlled, plasma protein does not affect growth or peripheral endocrine parameters in young pigs.