Dietary protein content and the subsequent body composition and food intake of pigs

Abstract

SUMMARYForty Large White × Wessex pigs were fed from 7 to 27 kg live weight, on diets containing either 28 or 14% crude protein. From 27 to 113 kg live weight the pigs were fed a common diet ad libitum. Pigs from each treatment were killed at 27, 54, 82 and 113 kg live weight and the chemical composition was determined. From 7 to 27 kg and from 27 to 113 kg live weight, daily gain, food intake and food conversion efficiency were similar for the two treatments.At 27 kg, pigs on the lower protein diet were fatter and contained less lean tissue. Between 27 and 54 kg live weight the pigs previously on the higher protein diet deposited a much greater amount of fat than the pigs on the lower protein diet, so that by 54 kg the pigs initially on the lower protein contained less fat. At 82 and 113 kg live weight the pigs given the lower protein diet initially also tended to contain less fat. These findings are discussed with particular reference to the voluntary energy intake of growing pigs.

Anatomical and chemical composition of female pigs and barrows of Danish Landrace related to nutrition

“…By using all 244 pigs in regression analyses it was found that the deposition of 1 g protein increased live weight by 5.8 g, and deposition of 1 g chemical fat increased live weight by 3.4 g. Investigations of the regression coefficients at 20 kg and 90 kg live weight indicated a positive quadratic term. WYLLIE and OWEN (1978) found that a quadratic term in the statistical model did not contribute much in explaining the total variation, when the content of protein and chemical fat was regressed against weight of empty body. The large variation in chemical composition of the pigs and of gut fill (2.4 kg to 10.0 kg at 90 kg live weight) on which the regression coefficients are based make them usable for control of balance experiments.…”

Use of plasma urea nitrogen as a rapid response criterion to estimate the lysine requirements of growing and lactating pigs

“…In some instances, rate of weight gain does not provide a good measurement of amino acid adequacy because of variations in composition of gain with age and/or dietary balance (Hogberg and Zimmerman, 1979). In the growing animal, direct or indirect assessment of protein gain provides a more precise assessment of amino acid adequacy (Brown et al, 1951;Smith et al, 1967;Wyllie and Owen, 1978) than does body weight gain.…”

Threonine requirement of the weanling pig and amino acid balance studies with pigs and chicks

“…This measurement, however, requires the use of laborious and expensive comparative slaughter techniques (Brown et al, 1951;Wyllie and Owen, 1978). Brown et al (1973) concluded that growth rate is a relatively poor indicator of amino acid requirements for lean meat production and it gives lower requirement estimates than feed conversion ratio or lean tissue deposition.…”