Absorption and Bioavailability of DL-Methionine Hydroxy Analog Compared to DL-Methionine

Abstract

Intestinal absorption of crystalline DL-methionine (DL-MET) and DL-methionine hydroxy analog calcium (DL-HMA) were determined in a true-digestibility-balance assay using cecectomized (CEC) and sham-operated conventional (CONV) cockerels. The treatments consisted of fasted birds and birds crop-intubated (CI) with 30 g of a corn-soybean meal basal diet (16% CP) supplemented with 0, .2, or .4% of DL-MET or equimolar levels of DL-HMA. There was no detectable free D-MET or L-MET or HMA in the excreta of fasted birds or of those fed the unsupplemented basal diet. The intestinal absorption of DL-HMA was 95.9 +/- .8% (means +/- SE) for CEC and 98.8 +/- .8% for the CONV cockerels. The absorption of DL-MET was approximately 99.7 +/- .2% for the CEC and the CONV cockerels. In a second experiment procedures were developed for a bioavailability assessment by comparing the growth responses to CI and intraperitoneal-injected (IP) DL-MET or DL-HMA in chicks fed a crystalline-amino-acid diet deficient in methionine. Graded increments of pH-adjusted DL-MET or DL-HMA (in water solutions) were administered twice daily in a 7-day growth assay. Slope-ratio analysis indicated that bioavailability (+/- SE) of CI DL-HMA was 91.3 +/- 11.8% relative to the CI DL-MET on an equimolar basis. The bioavailability of CI DL-HMA was similar to that of IP DL-HMA, indicating that the intestinal absorption of DL-HMA was highly efficient.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological efficacy and absorption of DL‐methionine hydroxy analogue free acid compared to DL‐methionine in chickens as affected by heat stress

“…This corresponds to a net absorption value of 90-8%, significantly lower than the net absorption of supplemental DL-methionine. Our value for the net absorption of MHA lies between that of Larbier (1988) and Han a al. (1990) for caecectomised birds.…”

“…The procedure was a modification of the Sibbald method as described by Han et al (1990). The cockerels were individually caged in a climatic chamber.…”

“…Data on the excretion in faeces and urine is conflicting. In some studies up to 17% of the dietary MHA appeared in the excreta (Saunderson, 1983;Larbier, 1988), whereas Han et at. (1990) found net absorptions of 95-9 and 98-8%, respectively, in caecectomised and intact birds.…”

Poly(A)+ RNA Encoding Proteins Capable of Transporting l-Methionine and/or dl-2-Hydroxy-4-(Methylthio) Butanoic Acid Are Present in the Intestinal Mucosa of Broilers

“…Differences in the amount of L-Met and DL-HMB transported might be related to the differences in the mechanism by which HMB and L-Met are transported. In vivo chicken experiments have shown that the small intestine had similar capacities to absorb DL-HMB and L-Met (4,18,19). However, when the mechanisms of transport were examined, L-Met transport appeared to be Na ϩ -and energy-dependent carrier mediated and HMB transport appeared to be comprised of Na ϩ -independent and proton-dependent carrier mediated and diffusion (3,4,20).…”

Scientific opinion on the safety and efficacy of L‐tryptophan produced by Escherichia coli (FERM BP‐11200) for all animal species based on a dossier submitted by Ajinomoto Eurolysine SAS

“…The apparent digestibility of crystalline L-tryptophan is about 100 %, as for most crystalline amino acids (e.g. Han et al, 1988Han et al, , 1993Izquierdo et al, 1988;Chung and Baker, 1992). However, microbial degradation (e.g.…”