[Performance-related lysine requirement of fattening pigs. 4. Effect of energy and amino acid intakes on composition of gain and derivation of lysine requirement].

The results show that protein and fat syntheses proceed simultaneously in growing swine. Reducing the energy intake during the 2nd half of the fattening period in pigs of modern genetic construction (hybrid pig) is likely to cut both fat and protein deposition per day. This will result in lower daily gains, a longer fattening period and higher energy expenditure. Therfore, it is not advisable to restrict energy supply during the 2nd half of fattening of pigs derived from modern breeding lines. The optimum amino acid : energy ratio allows to make full use of the protein deposition capacity in pigs with prefixed slaughter weight. For the limiting amino acid lysine it was found to be 10.5 g/1,000 energetic feed equivalents (swine) or 3 g/Mcal NEF (swine), and, taking into account amino acid digestibility, 9.5 g dig. lysin/1,000 energetic feed equivalents (swine) and 2.7 g dig. lysin/Mcal NEF (swine), respectively.