Effect of chronic immune system activation on body nitrogen retention, partial efficiency of lysine utilization, and lysine needs of pigs.

Abstract

The influence of a low and high level of chronic immune system (IS) activation on body nitrogen retention, partial efficiency of dietary lysine utilization, and lysine needs of pigs at three body weights was determined. All pigs were of a single genetic strain and geographical site of origin, and the low and high IS pigs were created by physically isolating pigs from or continuously exposing pigs to major vectors of antigen transmission. In each IS group, four littermate barrows in each of six litters were allotted at 25 d of age to one of four dietary amino acid regimens (.60, .90, 1.20, or 1.50% dietary lysine). Pigs were individually penned and allowed to freely consume feed from 6.2 to 26.5 kg BW. Nitrogen balance during 4-d periods was determined for each pig at BW of 10, 17.5, and 25 kg. Minimizing the level of chronic IS activation resulted in 4.7 to 7.7 g/d greater body nitrogen retention, 147 to 201 g/d greater BW gain, and 101 to 147 g more gain per kilogram of feed in pigs at the three BW. Dietary lysine intakes needed to maximize each of these criteria at BW of 10, 17.5, and 25 kg were a minimum of 2, 2, and 3 g/d greater in the low vs high IS pigs. However, the partial efficiency of lysine utilization for body nitrogen retention was similar between IS groups. On the basis of these data, the greater dietary lysine needs of the low IS pigs are due to their greater biological capacity for body nitrogen accretion and not to differences in their efficiency of dietary lysine utilization.

Effect of Repeated Sephadex Injection with or without Escherichia coli Lipopolysaccharide on Growth, Immunocompetent Organ Weight and Plasma Alpha 1 Acid Glycoprotein Concentration in Broiler Chicks Reared in Different Stocking Density

“…Animals reared in a dirty environmental condition activate chronic immune system and resulted in alternation of normal metabolic responses7,10). Metabolic responses to chronic immune system activation accompany with reduced rate of growth and feed utilization, and enlargement of liver and spleen in chicks and pigs5, 10,16,20). In the present study with chicks, immune stimulation induced by the injections of LPS and Sephadex on alternative days significantly reduced growth and feed intake with enlargement of liver and spleen.…”

Stressing food plants by altering water availability affects grasshopper performance

“…Consequently insect herbivores like species of the orders Orthoptera and Lepidoptera benefit from increased available nitrogen in their food plants (White 1976, Slansky andFeeny 1977). The statement that a higher nitrogen concentration in food plants often leads to faster growth rates in herbivores was postulated in a number of different studies (Traw et al 1996, Williams et al 1997, Hät-tenschwiler and Schafellner 1999. This is in accordance with the observed relationship between soluble protein content as well as amino acid concentration and body size, where individuals that fed on drought-stressed plants were larger and heavier than individuals grown under control or moisture conditions.…”

Whole-body β-oxidation of 18:2ω6 and 18:3ω3 in the pig varies markedly with weaning strategy and dietary 18:3ω3

“…Segregated early weaning (SEW) is a management strategy in which pigs are weaned at 10-14 days old instead of the more common 21 days old and are housed in a cleaner environment compared with nonsegregated weaning (NSW) used in conventional commercial units. SEW pigs eat more and grow faster, and there is some evidence that this is due to reduced antigen exposure, i.e., to less demand on their immune system (3)(4)(5)(6)(7)(8)(9).…”