Methionine+cystine requirements of growing pigs. Performance, nitrogen retention and carcass composition of growing pigs given semi-purified diets supplemented with graded levels of DL-methionine

Methionine requirements of weanling European pigs given cassava flour/soya bean meal diets

Forty-eight Large White × Landrace weanling pigs weighing initially 9·69 (s.e. 013) kg were used to evaluate the dietary methionine requirements of weanling European pigs reared under a humid, lowland, tropical environment. Response criteria used were growth rate, efficiency of food conversion, carcass quality, and the weights of some organs and individual muscles. The pigs (three male castrates and three females per treatment) were given a cassava flour-soya bean meal diet containing 202 g crude protein per kg dry matter and supplemented with increments of multiples of 0·8 g DL-methionine per kg diet. Total dietary methionine levels ranged from 2·3 to 7·9 g per kg diet dry matter. All diets contained 14·75 MJ digestible energy per kg dry matter. The experiment lasted 42 days, at the end of which the pigs were slaughtered at an average live weight of 17 kg.

Growth rate and feed efficiency were significantly improved when the basal diet was supplemented with DL-methionine (P< 0·001). No significant treatment differences in organ weight were found. Methionine requirement was significantly influenced by sex and age of the pigs, with castrates having lower requirements than females. Pooled estimated methionine requirements for optimum growth rate and efficiency of food conversion were 4·0 and 4·3 g/kg diet dry matter respectively. Maximum proportion of lean was recorded on the diet containing 3·1 g total methionine per kg dry matter.

Sweet lupin seed meal as a protein source for growing pigs

The growth performance, carcass quality and digestive efficiency of growing pigs were used to compare sweet lupin seed meal (SLSM) to soya bean meal and meat meal as a source of supplementary protein to wheat in diets for pigs, and to study the influence of low levels of lysine and methionine, high levels of crude fibre and oil, and possible toxic factors in SLSM on the use of SLSM in such diets.

The growth rate and food utilization of pigs between 20 and 80 kg live weight were in the order soya bean meal > SLSM > meat meal, but only the difference between soya bean meal and meat meal was significant. These feeds did not differ significantly in their effects on the proportion of lean in the ham. Adding lysine to the SLSM diet improved growth performance but adding methionine did not. The digestibility of crude fibre in diets containing SLSM was greater than that in diets containing soya bean meal; the digestible energy contents of SLSM and soya bean meal were 4·13±0·05 and 4·16±0·08 Mcal/kg dry matter, respectively. Pigs fed on a diet containing 27·5% SLSM grew faster but utilized food as efficiently when fed ad libitum as on a restricted scale of feeding. The subcutaneous fat of pigs fed on SLSM had a higher iodine number than that of pigs fed on soya bean meal.

Amino acid requirements of growing pigs 4. Methionine plus cystine

The response of the growing female pig (25 to 55 kg live weight) to increasing dietary methionine plus cystine concentrations was assessed by measurement of growth rate, food utilization, ham dissection and changes in blood metabolite concentrations. A range of 13 methionine plus cystine concentrations from 3·5 to 5·79 g/kg resulting from combinations of three basal diets and synthetic methionine, was studied. The diets were formulated using barley, a yeast protein, tapioca and synthetic amino acids to contain similar energy concentrations, 9·5 g lysine per kg diet, and adequate concentrations of other essential amino acids and non-essential nitrogen. They were offered once daily according to a restricted feeding scale.

Responses were interpreted by broken line functions which indicated, from the growth performance experiment, a requirement between 4·5 and 4·8 g/kg of the diet, when the complete range of methionine plus cystine concentrations was studied. The influence of a range of dietary methionine plus cystine concentrations from 4·1 to 5·3 g/kg diet on changes in plasma urea, methionine, lysine and threonine concentrations indicated a requirement for methionine plus cystine of 4·5 g/kg of the diet.

[The activity of and requirements for selected amino acids in growing female swine. 2. Methionine and cystine]

The methionine/cystine efficiency of ten protein sources including that of different charges of the same protein source was ascertained in N balance experiments with a total of 60 female pigs in the live weight range of 35-50 kg. The variability of the derived sulfur amino acids (SAS) efficiency coefficient (Csas) ranged between 0.64... 0.91 based on the SAS efficiency of casein as a standard. There was an analogous differentiation for the derived requirement values on the basis of the analysed methionine/cystine values of the proteins. For a protein retention of 100 g/day and a live weight of 40 kg, 6.2g methionine/cystine was ascertained based on the highest SAS efficiency (Csas = 1) as yet.

[Activity of and requirement for selected amino acids in growing female pigs. 1. Lysine]

In N balance experiments with a total 59 growing female pigs in the live weight range of 33 to 55 kg the lysine efficiency (bc-1 value) and the lysine efficiency coefficient (kLys) of various cereal proteins were ascertained under the consideration of various charges and varieties. The range of kLys = 0.65 ... 0.96 shows a wide spectrum of lysine efficiency, which results in an analogous differentiation of the derived lysine requirement values. Assuming kLys = 1.0 (lysine efficiency 100%, i.e. the maximum value for bc-1 found as yet for native proteins) a daily lysine requirement (efficient amino acid) of 8.9, 10.8 and 12.6 g resp. was ascertained for 100 g daily protein retention at 30, 40 and 50 kg live weight resp.

The utilization by pigs of methionine from five protein concentrates compared with synthetic methionine

Pigs (n 100) between 28 and 56 d of age were given diets containing one of five protein concentrates ad lib. The utilization of methionine from the protein concentrates was compared with synthetic methionine. Increasing the methionine content of the diets from 1.5 to 2.2 g/kg diet increased the weight gains of the pigs from 61 g/d to 198-292 g/d. The feed conversion efficiencies decreased from 2.56 to 1.34-1.56. The utilization of methionine from the protein concentrates for weight gain, as compared with synthetic methionine, was meat meal A 0.89, meat meal B 0.97, soya-bean meal 1.02, cotton-seed meal 0.87 and dried skim milk 1.04.

Amino acid oxidation by young pigs receiving diets with varying levels of sulphur amino acids

Piglets were weaned at 3 d of age and were introduced to liquid diets in which 400 g/kg protein was supplied as skim-milk powder and the balance as a mixture of free amino acids. The skim milk contributed 2.3 g methionine and 1.4 g cystine/kg diet; the experimental diets were made by supplementing these levels with free amino acids. The adequacy of the test level of the amino acid in the diet was assessed by measuring the oxidation of [1-14C]phenylalanine as an indicator of the partition of the essential amino acids between incorporation into protein and degradation. Radioactivity recovered as carbon dioxide was used as a measure of catabolism. Addition of 0.2, 0.4, 0.7, 1.2 and 1.7 g L-methionine/kg to a diet containing 5 g cystine and 3 g choline chloride/kg showed that phenylalanine catabolism was minimal for the diet with 2.7 g methionine/kg indicating that this is the dietary requirement for methionine to serve as a source of methionine residues for protein synthesis. Addition of D-methionine to produce a series of diets with graded levels of methionine showed that the D-isomer was less effective than the L-isomer in reducing phenylalanine catabolism: the addition of 0.8 g D-methionine/kg diet was needed to produce the same effect as 0.4 g L-methionine/kg diet showing that the replacement value of D-methionine for L-methionine was 50% in the young pig.(ABSTRACT TRUNCATED AT 250 WORDS)

[Effect of graded protein supply at high-energy level on the fattening performance and the retention and utilization of feed energy, protein and amino acids by female fattening swine. 3. N retention and N and lysine metabolism determined by N balance and N analysis of the carcasses]

The slaughtering of female fattening pigs differently supplied with protein and lysine (nearly constant proportions) showed that a high supply (III) in comparison to the standard supply (II) did not bring about better results. The lower consumption of digestible crude protein and lysine (I) resulted in a prolonged fattening period, lower daily protein retention (by 23%) and a lower content in live weight growth (by 5%). The two feeding variants I and III are therefore ineconomical and not recommendable. There are significant positive correlations between N-retention calculated from 3 N-balance measurings in the first fattening period (up to the 44th fattening day) and N-deposit ascertained after the analysis at the carcasses at the beginning and at the end of fattening. By means of the calculated estimate functions (1) y = 4.724 + 0.5432x and (2) y = 7.850 + 0.4961x the level of the real protein deposition (y) in the total fattening period can be derived from the N-balance (x) both in g per animal and day (1) and in g per kg live weight growth (2). The four complexes of causes for the differences in N-retention according to N-balance and N-deposit according to carcass analysis: 1. high N-deposition in the first fattening period; 2. unascertainable N-losses 3. the difference between slaughtering and total body weight and 4. physiologically caused deviations in the N-storage of the living organism, are discussed. Protein and lysine utilisations are comparable with values from literature achieved under similar conditions. In the group supplied according to standard (II) it is 29.5 and 45.6% resp. or, related to the digested quota, 36.6 and 57.7% resp. Here the protein (10.1 kg) and lysine (1,640 g) assigned for a live weight growth of 80 kg (35-115 kg) in 100 fattening days were consumed, which means that 162 g lysine were needed for 1 kg deposited protein.