Pig breeds respond differently to nutrient supply
Take Home Message: Large White pigs are leaner than Duroc but feeding a low protein diet results in greater fat levels in Large White pigs, and nutrient supply must therefore be matched to pig genotype.
Different pig breeds respond differently in terms of fat deposition to the levels of nutrients supplied, particularly protein and energy. “And so it is necessary to balance diets to genotypes, particularly for leaner genotypes such as large whites, to avoid excess levels of fat deposition within the body,” Bristol University’s Gary Stonehouse told delegates at this year’s British Society of Animal Science annual conference.
“Protein is an expensive nutrient in pig diets and high protein diets lead to high N excretion, a source of pollution. Low protein nutritional strategies are therefore needed, but these often increase fat deposition.
“So our study compared three nutritional strategies differing in protein and energy supply using genotypes with different propensities for fat deposition,” he said, explaining the rational behind his team’s work.
A total of 192 entire male pigs – half 0.75 Duroc (D) and half 0.75 Large White
(LW) – were fed ad lib from 40kg to 120kg liveweight on one of three nutritional strategies.
The pigs were group fed with eight animals per pen, on a breed x nutritional strategy basis. The dietary protein content was reduced across the strategies, with the concentration of lysine and other amino acids being reduced in relation to protein. The pigs were reared at Harper Adams University College then transported to the University of Bristol abattoir, where they were slaughtered and dissected.
“And the result showed that the values in Duroc were similar across the nutritional
strategies, while a greater response to nutritional strategy was found in
LW, where the amount of fat increased significantly across the diets,” said Mr Stonehouse.
“The same pattern was also found for the concentrations of intramuscular fatty acids in the longissimus dorsi muscle and in the subcutaneous adipose tissue depot in LW.”
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