No abstract

-The absorption of β-carotene in pigs is limited. Nevertheless β-carotene might positively affect reproduction. In this study the absorption and tissue distribution of β-carotene as well as its function as precursor of vitamin A was investigated in gilts that were fed according to one of three dietary treatments: VA (4 000 IU vitamin A), VA + VA (4000 IU + 8300 IU) and VA + BC (4000 IU + 100 mg β-carotene per kg diet) for 14 weeks. Only in the VA + BC group was β-carotene detected in plasma (1-8 ng . mL -1 ), liver, adrenals and corpora lutea, indicating that pigs absorb intact β-carotene at low rates. Liver levels of vitamin A were higher (P < 0.01) at comparable levels in the VA + VA and VA + BC group than in the VA group, indicating a conversion rate of β-carotene to vitamin A of 40 to 1 on the basis of weight for β-carotene at this level (100 mg . kg -1 ) in the diet. Higher levels of vitamin A in the uterus of the VA + BC group (P < 0.01) as well as the accumulation of β-carotene in adrenals and corpora lutea might reflect some influence of β-carotene on local vitamin A metabolism which might be of importance for reproductive performance in gilts.pig / metabolism / absorption / tissue distribution / β-carotene / vitamin A Reprod. Nutr. Dev. 41 (2001) 47-55 47

No abstract

The time course of plasma amino acid concentrations was studied in adult rainbow trout (300 g mean body weight). After a starvation eriod of 2 days fish were force-fed either with fish protein concentrate or a mixture of acidic casein an8 Na-caseinate at a rate of 0.32% CP (N ' 6.25) of bod weight. Peak levels occurred for feeding fish protein concentrate 6-12 h and for the casein mix 18 bost-feeding. The increase of the essential amino acids was closely correlated to the amino acid pro e of the test proteins, whereas the concentration differences of the non-essential amino acids were at no time correlated to the amino acid pattern of fish protein concentrate or even negatively correlated in case of casein. The limiting amino acids in the test proteins were determined by ranking the average concentration increases (decreases) of the individual essential amino acids. Accordingly, arginine and histidine were most deficient in casein; in fish protein concentrate tryptophan seems to be the first limiting amino acid, followed by isoleucine.

No abstract