[The determination of a gross utilization of 15N-lysine in laboratory rats. 2. Comparative testing with an antibiotic supplement to the diet].
Wistar rats of a live weight of about 100 g received in 26 groups (4 animals/group) diets, each with a different lysine content. The rations given supplied the animals with 75%, 100% or 125% lysine of the calculated requirement. The source of protein in the diets was: barley (B), wheat (W), wheat gluten (WG), isolated soybean protein (assay protein) (S) or soybean meal (SM). For WG and S only the lysine levels 100% and 125% (SM = 116% and 125%) could be achieved. All diet groups were fed for 10 days with and without antibiotics (7 g Nebacitin/kg feed-DM). During the 7-day-period of the main experiment all 24 rations were supplemented with 0.5 g 15N-lysine/kg DM (48.3 atom-% 15N-excess, alpha-aminogroup 95% 15N-labelled). The nitrogen balance was improved only after feeding antibiotics with the diet S 100. It may be supposed that Nebacitin saved the second limiting amino acid methionine against microbial degradation in the digestion tract. The biological value (BV) of feed-proteins declined in the case of the diets B and W in the presence of antibiotics because the absorbed nitrogen was higher, this calculation basis for BV was therefore also higher without an improvement of the N-utilization. The 15N-excretion in faeces was significantly lower after feeding the diets B, W and WG with antibiotics. The 15N-excretion in urine was elevated in the most cases of the antibiotic supplement. The determination of a gross utilization of lysine and 15N-lysine resp. in relation to the lysine retention (availability) was not possible, neither using a labelling of diets with 15N-lysine.
Institut für Ernährungsphysiologie, Humboldt-Universität zu Berlin, Germany.
H
H
Bergner
H
H
Schwandt
J
J
Lenk
D000284:Administration, Oral; D000821:Animal Feed; D000818:Animals; D001414:Bacitracin / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D004044:Dietary Proteins / Q000378:metabolism; D004063:Digestion; D004359:Drug Therapy, Combination / Q000008:administration & dosage / Q000494:pharmacology; D005243:Feces / Q000737:chemistry; D005527:Food, Fortified; D005983:Glutens / Q000008:administration & dosage; D001467:Hordeum; D008239:Lysine / Q000008:administration & dosage / Q000378:metabolism*; D009355:Neomycin / Q000008:administration & dosage / Q000494:pharmacology*; D009584:Nitrogen / Q000378:metabolism; D014674:Plant Proteins, Dietary / Q000008:administration & dosage; D051381:Rats; D017208:Rats, Wistar; D030262:Soybean Proteins; D013025:Glycine max; D014908:Triticum; D015430:Weight Gain
D004044:Dietary Proteins; D014674:Plant Proteins, Dietary; D030262:Soybean Proteins; D001414:Bacitracin; D005983:Glutens; C003903:Nebacetin; D009355:Neomycin; D008239:Lysine; D009584:Nitrogen
Untersuchungen zur Bestimmung einer Bruttoverwertung von 15N- Lysin an Versuchsratten. 2. Mitteilung. Vergleichende Prüfung bei einer Antibiotikazulage zur Diät.