Serum insulin‐like growth factor‐1 concentration in pigs divergently selected for daily food intake or lean growth rate

Abstract

Summary Divergent selection over seven generations for daily food intake (DFI) and for two lean growth rate (LGA and LGS) selection objectives in pigs produced correlated responses in serum insulin‐like growth factor‐1 (IGF‐1) concentration. The LGA and LGS selection objectives were for lean growth, but with performance testing on ad libitum (LGA) or on restricted (LGS) feeding regimes. There were 342 animals in the study, with an average of 46 pigs in each selection line and 72 pigs in the control line. All animals were performance‐tested from 30 to 90 kg on an ad libitum feeding regime. Selection on DFI increased IGF‐1 at 6 weeks of age (158 versus 104 μg/l, SED 21; control 136 μg/l) and selection for high LGA increased IGF‐1 at 30 kg liveweight (202 versus 161 μg/l, SED 14; control 185 μg/l). At 6 weeks of age and at 30 kg of weight, there was no response in IGF‐1 with selection on LGS (128 versus 129 and 167 versus 153 μg/l, respectively) suggesting that IGF‐1 may not be a reliable physiological predictor of genetic merit for such a selection objective, which combined rate and efficiency of lean growth. IGF‐1 measured immediately prior to the start of performance test may be useful in determining which animals to performance test for a lean growth selection objective, whereas IGF‐1 measured at 6 weeks of age may be a useful physiological predictor of genetic merit for daily food intake during performance test.

Insulin-like growth factor-I measured in juvenile pigs is genetically correlated with economically important performance traits

“…These results were consistent with estimates from Lamberson et al (1995) and QAF1, reported in Luxford et al (1998a). Poorer data structure in the remaining trials made it difficult to accurately separate additive genetic from common litter effects, as was also observed in the study of Cameron et al (2003). Overall, larger variances were observed in trials with higher mean IGF-I concentrations.…”

“…These results are consistent with the usual consequences of selecting for improved lean growth efficiency on meat quality traits (see Lonergan et al 2001), even without using information on IGF-I concentrations to facilitate selection decisions. Cameron et al (2003) performance tested 342 descendents of 6 selection lines and a control line, maintained without selection for the previous 5 generations, in a study involving 2 nutritional regimes. All animals were recorded for IGF-I at 6 weeks of age, at 30 kg, and at 90 kg before and after fasting.…”

Effect of plant extracts on growth performance and insulin-like growth factor 1 secretion in growing pigs

“…Circulating IGF-1 concentrations were significantly correlated with the body size in three types of swine, which differed in growth rate and mature body weight, suggesting that IGF-1 is involved with the in vivo regulation of swine growth . However, Cameron et al (2003) reported that serum IGF-1 was useful to predict ADFI physiologically, but not ADG and backfat depth, at six weeks of age. Studies demonstrated the relationships between plasma IGF-1 and growth performances, showing positive and negative correlation of plasma IGF-1 concentration at 25 kg BW, with estimated lean percentage at 90 kg.…”

Analysis of Association Between a Microsatellite at Intron 1 of the Insulin-Like Growth Factor 1 (IGF1) Gene and Fat Deposition, Meat Production and Quality Traits in Italian Large White and Italian Duroc Pigs

“…Additional studies should evaluate the effects of this polymorphic microsatellite on performance traits at early ages. Effects of this polymorphism on circulating IGF1 content, that was reported to be correlated with several production traits in growing pigs (Lamberson et al, 1995;Cameron et al, 2003) should also be investigated. In addition, the implementation of a selective genotyping approach on other traits, e.g.…”

“…In pigs, blood serum IGF1 concentration has been genetically correlated with daily feed intake, residual feed intake, growth rate, lean meat deposition, back fat thickness (BFT), carcass weight and intermuscular fat content. Associations showed some differences (in some cases not fully concordant) depending on the age of the animals, the breeds/lines and the experimental designs, with potential practical applications in predicting genetic merit of the pigs (Taylor et al, 1992;Lamberson et al, 1995;Cameron et al, 2003;Te Pas et al, 2003;Suzuki et al, 2004;Lee et al, 2005;Estany et al, 2007;Hoque et al, 2009;Bunter et al, 2010). By using transgenic pigs expressing a human IGF1 cDNA, Pursel et al (2004) showed that these animals were leaner than control pigs, suggesting that expression of IGF1 in skeletal muscle altered body composition in adult pigs without any effects on growth performances.…”