Determination of the biological value of a protein source with a supposedly ideal amino acid balance (a.r.c. 1981) for the young pig (10 to 20 kg liveweight)

Moughan, Paul J.; Smith, W. C.; Cornwell, Julie K.

doi:10.1002/jsfa.2740380202

Cited by 6 publications

(1 citation statement)

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“…The efficiencies of N retention for the casein and FAA diets were low compared with estimates made by N balance (Moughan et al 1987;Chung & Baker, 1992). The difference in methodology is important because Newport & Henschel(l984) showed that N balance overestimates N retention in the carcass by 16-25 %.…”

Section: Effect Of Methodology On Nitrogen Retention Estimatesmentioning

confidence: 83%

Comparison of growth performance and nutrient retention of weaner pigs given diets based on casein, free amino acids or conventional proteins

1997

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In two experiments the potential value of diets based on casein or free amino acids (FAA) for amino acid utilization experiments were examined. In Expt 1 the optimum dietary electrolyte balance (dEB) for a casein-based diet was estimated by supplemention with 10 or 20 g NaHC03/kg, to produce diets containing 64, 183 or 302 mmoykg. In addition, piglet growth performance and efficiency of nutrient deposition of piglets given the casein diets were compared with two multiple protein source diets; Supercreep, a commercial multiple protein source diet or CFS (casein-fishsoyabean-sugar) or a FAA-based diet. Expt 2 was designed to compare piglet response to FAA diet stored at -15" with twice daily feeding, with FAA diet stored at ambient temperature (13-30') and offered ad libitum. A CFS diet was used as a positive control and the experiment was conducted over the 10-20 kg growth phase. Expt 1 used forty-eight piglets weaned at 20-22 d of age and albcated to one of six treatments formulated to contain at least 0-84 g lysine/MJ digestible energy in a randomized block design. Piglets given the CFS and Supercreep diets produced superior growth rates (518, 491 gld) to those given a FAA diet (353 gld) or casein diet containing 0, 10 or 20 g NaHCO&g respectively (365,417,390 gld) between 5 and 20 kg live weight. Piglets given the casein and FAA diets had higher amino acid digestibilities than those given the Supercreep and CFS diets. The increase in the dEB of the casein diet from 64 to 183 mmoVkg improved piglet growth performance between 5 and 20 kg by 14 %. All piglets given casein diets had similar ileal and faecal digestibilities, empty-body compositions, nutrient deposition rates and retention ratios. The results of Expt 2 showed that there was no beneficial effect on piglet performance of storing the FAA diet at -15" and feeding twice daily. Based on the results of these two experiments, neither the casein (0, 10, 20 g NaHC03/kg) nor FAA diets were suitable for estimating amino acid utilization by the piglet. There remain unidentified factors which l i t the growth performance of piglets given the casein and FAA diets.Casein: Amino acids: Pigs A diet formulated on an ideal protein basis, with protein digestibility close to 1, would provide an excellent reference diet for the study of amino acid utilization. This reference diet could be used to identify causes of inefficient utilization of amino acids in diets containing traditional protein sources. The efficiency of utilization of amino acids is typically measured using N balance and/or empty-body retention. Yet there are no empty-body estimates in the literature for the efficiency of utilization of diets (which have been formulated on an ideal protein basis) that contain highly digestible protein sources.

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Section: Effect Of Methodology On Nitrogen Retention Estimatesmentioning

confidence: 83%