Effect of selection for growth on normal and reduced protein diets on weight gain, feed intake, feed efficiency and body composition in mice

Abstract

Mice selected for weight gain from 3 to 9 weeks of age on a normal (N) protein diet containing 19.3% protein and a reduced (R) protein diet with 5.1% protein were reared on both diets in generations 7 and 9. The lines NH, NC, NL, RH, RC and RL (H, high; C, control; L, low) were tested for weight gain on diet N and R and for feed intake and feed efficiency on diet N in generation 7. In generation 9, the lines were tested for body composition traits (fat, protein and water percentage) at 3, 6, 9 and 12 weeks of age on both diets. A significant (p < 0.0001) genotype x environment interaction for growth rate was observed in generation 7. Weight gain at both the protein levels was best improved by selection at the protein level itself. Furthermore, the ranking of the lines on diet N was similar for weight gain, feed intake and feed efficiency. In generation 9 at 9 weeks of age, the ranking of the lines for fat percentage was equal to the ranking for weight gain in generation 7 on both test-diets. The association between weight gain and protein or water percentage was less pronounced, particularly on diet R. These results suggest that the largest genetic improvement in growth rate is obtained when the protein content of the feed is the same in selection and production. However, when selection is carried out in one environment while the animals have to perform under conditions with varying nutrient protein contents, selection in an inferior environment may be advantageous.

Genetic parameters and effect of selection for body weight in lines of mink (Neovison vison) on ad libitum and restricted feeding

“…When growth in body length has ceased, a period with fat deposition and maturation of the fur follows, and selection is performed in late November. Only few experiments have examined the effect of selection at later ages (McPhee & Neill, 1976;Nielsen & Andersen, 1987;Urrutia & Hayes, 1988b;Nielsen & Korsgaard, 2006) although Hayes and McCarthy (1976) suggest that selection for growth at different ages may exploit different genetic variation. Recording of both August and November weight allows test of this hypothesis in the present experiment.…”

Selection for Adaptation to Dietary Shifts: Towards Sustainable Breeding of Carnivorous Fish

“…Besides, there is growing evidence that changes in feeding can drive evolution, as demonstrated in stickleback [4], lizards [5] or in human sub-populations [6], [7], [8], [9]. Evidence of rapid dietary-induced genetic changes can also be seen from within-population experimental selections in animal models [10], [11]. Selective breeding of carnivorous fish for aquaculture may take advantage of this plasticity to address an especially challenging feeding context by promoting such genetic adaptation in farmed fish populations fed with non-marine diets.…”

Response to selection and genotype–environment interaction in mink (Neovison vison) selected on ad libitum and restricted feeding

“…The AL and RF lines were selected for high November weight on ad libitum and restricted feeding. The FC line was selected for low feed conversion ratio on ad libitum feeding Nielsen and Korsgaard (2006) in mice and by Pym and Nicholls (1979) in poultry. Cameron (1994) found no change in feed consumption when selecting for lean growth rate in pigs probably as the selection criterion used was constructed to reduce backfat.…”

“…On restricted feeding, improved feed conversion ratio may be obtained by an improved partitioning of energy for growth. Few studies have examined the effect of selection after maturity (Nielsen and Andersen 1987;Urrutia and Hayes 1988a;Nielsen and Korsgaard 2006). Such experiments are important to fur animal production as, for example, mink are selected in late November, while body length growth stops in late August/September (Charletlery et al 1979;Hansen and Glem-Hansen 1980;Hansen 1997).…”