The responses of growing pigs, of different sex and genotype, to dietary energy and protein

Abstract

Intact male pigs from two nucleus breeding herds (one predominantly Duroc, DM; the other purebred Large Wliite, LM) together with intact male (RM), castrated male (RC) and female (RF) commercial hybrid pigs were given one of two diets, with the same balanced protein (180 or 240 g/kg) at three daily rates, the highest being 'to appetite'. Six replicates of 30 pigs were allocated to these regimes at 40 kg: one replicate was slaughtered immediately to determine initial carcass composition; the remaining pigs were slaughtered at 85 kg when carcass fat and specific gravity (SG) were measured. For two replicates this was followed by dissection and chemical analysis: daily gains of carcass lipid and protein were estimated directly for these two replicates and predicted from carcass weight and SG for the other three. Fed 'to appetite', castrated males and females ate more than males; LM pigs ate least. All males grew faster than females or castrated males, the DM pigs the fastest, these rankings being relatively insensitive to feeding level. However, both in daily weight gain and daily protein accretion only the males responded to additional dietary protein. Daily body protein accretion of DM pigs increased linearly with intake on both diets whereas LM pigs showed little response to the highest level of feeding. At the same daily protein intake all pigs had higher rates of body protein accretion on the low protein diet, showing that they were sensitive to additional dietary energy. Results indicate that an animal's superiority may result from a greater efficiency of protein utilization or a higher lean growth potential but that these two characteristics are not simply related.

Effects of the dietary protein content and the feeding level on protein and energy metabolism in Iberian pigs growing from 50 to 100 kg body weight

“…In this way an appropriate balance between ideal CP and energy concentrations can be established and the response of the animals to changes in energy or amino acid (AA) supply can be predicted. To achieve our objective, the optimal supply of dietary ideal CP leading to maximum daily rates of PD (PD max ) and the marginal efficiency of body PD (Fuller et al, 1995), i.e., the change in daily PD per unit change in daily ME at restricted intakes (DPD:DME; g/MJ), were considered. A second objective was to establish reliable estimates of energy utilisation in the growing-fattening pig.…”

Ractopamine hydrochloride and immunological castration in pigs. Part 1: fresh belly characteristics for bacon processing and quality

“…resistance while the genetic Topigs turns out to produce animals with high meat quality, according to Fuller et al (1995). Table 3 presents the results for bacon quality parameters, determined using digitally imaged data.…”

An analysis of the composition of gain and growth of primal cuts of Iberian pigs of 10 to 150 kg body weight as affected by the level of feeding and dietary protein concentration

“…Kyriazakis et al (1995) observed the same net eff iciency in entire male Large White × Landrace and pure Chinese Meishan pigs. Fuller et al (1995) used Duroc, purebred Large White and a commercial hybrid. The re-examination of their data reveals that below PD max the regression line has a common slope, indicating equal efficiency at suboptimal intakes (Sandberg et al, 2005).…”