The effect of heat on amino acids for growing pigs

Abstract

Experiments were conducted to determine the effect of heating field peas (Pisum sativum) on the N balance and urine, serum and plasma composition of growing pigs. In the first experiment, four diets containing raw field peas (cv. Wirrega) (cv. Wirrega) or 165" (cv. Wirrega) had a significantly lower (P c 0.01) daily output of urea and uric acid in the urine, and depressed serum protein and serum urea concentrations. P h a lysine concentration and daily urine lysine output were not significantly different (P > 0.05) in pigs fed OD heated peas. Protein excretion in the urine of pigs fed on diets containing peas heated to 165" increased 3-7 times (depending on estimation technique) the level observed in pigs fed on diets containing raw peas. A second experiment was conducted to determine the apparent ileal digestib~ty of N and amino acids in cv. Wmega field peas. This study revealed that N digestiiility (044) and lysine digestibility (0.35) in peas heated to 165" were significantly lower than the cv. Dundale estimates (0.57 and 0-62 respectively) used in diet formnlations. The depressed serum and urine variables in pigs fed on heated peas were attributed to overestimation of digestibility.The results exemplify the fact that it is not possible to draw general conclusions as to the effects of heat on any particular protein concentrate. Variability in N balance experiments and problems associated with urine analysis are suggested as likely reasoms for the carrent study not reflecting poor utilization of ileal digestible lysine from heat-treated field peas. Despite considerable variation in the results, it is possible that a large proportion of non-utilizable amino acids in heated field peas may be excreted from the pig via the urine in the form of a protein.Field peas: Heat treatment: Nitrogen: Pigs Amino acid availability measurements have been shown to reflect the poor utilization of * Present address: Northfield

The effect of heat on amino acids for growing pigs

“…Heat-processed meal Field peas were used as the protein concentrate (Table 1). Graded levels of heat at 1 lo", 135", 150", or 165" were applied to batches of field peas and maintained for 15 min using a forced-air dehydrator (van Barneveld et al 1994). These levels were chosen because they are indicative of the levels of heat that can be obtained during the processing of commercial meals used in pig diets, and they should produce lysine availabilities varying from 0.90 down to 0.30, similar to those reported in commercial meals by Batterham et al (1984).…”

“…These levels were chosen because they are indicative of the levels of heat that can be obtained during the processing of commercial meals used in pig diets, and they should produce lysine availabilities varying from 0.90 down to 0.30, similar to those reported in commercial meals by Batterham et al (1984). The digestible energy values of the raw and heat-treated field peas were determined previously using total faeces collection (van Barneveld et al 1994). As discussed by van Barneveld et al (1994), lysine digestibility in field peas was not decreased by heating to 150', and hence an additional heat treatment of 165' was deemed necessary.…”

“…The digestible energy values of the raw and heat-treated field peas were determined previously using total faeces collection (van Barneveld et al 1994). As discussed by van Barneveld et al (1994), lysine digestibility in field peas was not decreased by heating to 150', and hence an additional heat treatment of 165' was deemed necessary. As a consequence, the present study has also been completed in two parts.…”

“…The ileal digestibilities of amino acids in the five field-pea treatments were determined using ileal cannulation and the direct ileal sampling technique (van Barneveld et al 1994). The ileal cannulation experiment was divided into two parts, the first determining the ileal digestibility of amino acids in the raw, 1 lo", 135", and 150" treatments, and the second the ileal digestibility of amino acids in the raw and 165" treatments.…”

“…The overall objective of this series of studies was to define the relationships between the application of heat to protein concentrates and total amino acids, the ileal and faecal digestibilities of amino acids, lysine availability and lysine utilization. In the first paper, van Barneveld et al (1994) reported that the application of graded levels of heat to field peas had little effect on the apparent ileal digestibility of amino acids. Only lysine showed a significant decrease with heating to below that recorded for raw peas (raw, 0.75; 165", 0.62).…”