Utilisation des protéines du lait et du lactosérum par le jeune veau préruminant. Influence de l'âge et de la dénaturation des protéines du lactosérum

Abstract

RésuméTrois aliments d'allaitement (Témoin, RD et

Proteins in the digesta of the pig : amino acid composition of endogenous, bacterial and fecal fractions

“…The composition of axenic feces is far from that of the two types of meconium (table 2), but relatively close to the mean composition of the two meconiums ( X 2 = 54). This X 2 value is similar to that recorded ( X 2 = 43) when comparing the feces of our axenic piglets with calf meconium of non-specified anatomical origin (Grongnet et al, 1981) or when comparing ( X z = 54) these same axenic piglet feces with axenic lamb feces (Combe and Pion, 1977). Our very pure endogenous sources (meconium, axenic piglet feces) can also be compared to samples obtained from older conventional pigs and considered as representative of an endogenous fraction, such as effluent of perfused isolated intestinal loop (Buraczewska, 1979) and duodenal or jejunal mucus recovered from various sites in small intestine (Darcy, Laplace and Duée, 1983 (Work and Dewey, 1953 ;Dufva et al, 1982).…”

Digestibility, blood levels of nutrients and skin responses of calves fed soyabean and lupin proteins

“…They were higher than the value obtained with an antigenic soyabean flour (0.80, Caugant et al, 1993a) and were similar to those observed with non-antigenic alcohol-treated soyabean concentrates (0.84, Caugant et al, 1993a;0.90, Guilloteau et al, 1986) Bush et al, 1992). Assuming that faecal N digestibility for whey was 97% that of SMP (Grongnet et al, 1981 ), values calculated for the soyabean and lupin concentrates (0.84 and 0.86, respectively) were lower than at the end of the ileum. However, they still compared well with values reported for non-antigenic alcohol-treated (0.89, Guilloteau et al, 1986;0.81 Lall6s ef al, 1994) (Combe et al, 1980;Souffrant, 1991).…”

“…This method uses a multiple regression analysis to establish the theoretical mixture which minimizes the x 2 distance with regard to the AA compositon of digesta. The mean composition of axenic lamb faeces (Combe, 1976) and calf meconium (Grongnet et al, 1981) was used as a model of undigested endogenous protein. The mean composition of pig (Mason et al, 1976) and sheep (Mason, 1979) faecal bacteria was used to represent the composition of gut bacteria.…”

A new method of estimating the proportions of different proteins in a mixture using amino acid profiles: application to undigested proteins in the preruminant calf

“…The proportions of the 3 reference proteins which gave the &dquo;best fit&dquo; with the actual amino acid profile of the diet based on skim-milk were found to be 0.17, 0.69 and 0.13 respectively. The summary statistics given in (Grongnet et al, 1981). Likewise, values for intestinal bacteria could be derived from mean values of amino acid compositions of bacteria isolated from pig faeces and bacteria isolated from sheep feces (Mason, 1979 (Mason, 1979).…”

“…Similarly, the amino acid composition of undigested endogenous protein can be derived from that of calf meconium (Grongnet et al, 1981) or feces of germ-free milk-fed lambs (Combe, 1976 (Gordon, 1981 ) (Evans et al, 1975), the present model has the advantage of giving the same weight to each amino acid and can be easily executed with the aid of computer programs for multiple regression analysis. Furthermore, the result is supported by statistical analysis which can be useful to test the validity of the fit and the significance of the calculated proportions in the mixture.…”