Responses in wool growth, liveweight, glutathione and amino acids, in Merino wethers fed increasing amounts of methionine protected from degradation in the rumen

Abstract

The aim of the experiments reported was to evaluate the protection from microbial breakdown of two methionine formulations (Lactet and Mepron) and to measure responses in wool production, liveweight, amino acids and glutathione in blood and tissues when one of these forms of methionine (Lactet) was supplied to merino wethers fed at maintenance. Lactet was well protected against microbial breakdown in the rumen. Peak values for concentrations of methionine in plasma, following administration of the different forms of methionine into the rumen, were 574, 148 and 143pmol L-1 for Lactet, DL-methionine and Mepron. Production responses to dosed levels of Lactet (0, 1, 2, 3, 5, 8 g methionine dayw1) were measured over 63 days in the animal house. Significant linear responses were obtained for wool growth (4-38%), fibre diameter (0.5-2 8m) and liveweight gain (30-1 15%). Concentrations of reduced glutathione in blood, liver and skin were increased, at some times during the experiment, by provision of Lactet. However, responses were inconsistent and highly variable among sheep, Glutathione was of limited use as an indicator of sulfur amino acid intake or status. Sulfate in plasma increased markedly at all levels of Lactet intake, and there was a linear relationship between Lactet intake and the concentration of sulfur in wool. Plasma free methionine and the ratio of methionine to total essential amino acids showed significant linear responses to the supplements. It was concluded that Lactet was an effective method of supplying rumen-protected methionine to ruminants.

Increased efficiency of wool growth and live weight gain in Merino sheep fed transgenic lupin seed containing sunflower albumin

“…According to published reports of responses to dietary supplementation with rumenprotected methionine (Lactet 1 ), 0.6 g of methionine should increase wool growth by between about 3 and 7%. 8,9,13 Similar responses have been reported when methionine has been administered via the abomasum. 27,28 The observed responses in wool growth (8%) and live weight gain (7%) in the current experiment are consistent with almost all the extra methionine in the transgenic lupin seed being protected.…”

Ruminal Fermentation, Growth Rate and Methane Production in Sheep Fed Diets Including White Clover, Soybean Meal or Porphyra sp.

“…The supply of essential amino acids relative to total energy supply influences the absolute and relative rate of protein and fat accretion in lambs. It is well documented that methionine and cysteine are the primary limiting amino acids for wool production and both wool production and live weight gain can be improved by supplementing sheep with methionine [43]. Gaillard et al [9] showed that most of the seaweeds investigated (Porphyra incl.)…”

Effect of Feeding on Salt Tolerant Plants on Physical and Chemical Properties of Coat Fibers in Sheep

“…This result concluded that haylage could increase palatability causing an increment in feed intake and in turn, increasing in amino acids. It is well known that Methionine amino acid increased the efficiency of conversion of metabolisable protein to wool and in turn increased wool production (Mata et al 1995). However, Ward (1998) found that wool contains higher concentrations of serine and Arginine, as well as Cysteine.…”

“…Methionine has been shown to cause rapid increases in fiber growth (Sahoo and Soren, 2011). Provision of protected methionine to adult withers fed to maintenance increased the efficiency of conversion of metabolisable protein to wool from 12.3% to 17.2%, and increased wool production from 9.6 to 13.5 g/d (Mata et al, 1995). On the other hand, Imik and Gunlu (2011) have found that the elasticity, length and diameter of wool fibers have not significantly differed with sorghum uptake.…”