Milk replacers containing isolated soybean protein for preruminant lambs: influence of experimental design on estimates of requirements for supplementary methionine

1978 ◽  
Vol 29 (5) ◽  
pp. 1031 ◽  
Author(s):  
DD Phillips ◽  
DM Walker

Preruminant male crossbred lambs, aged 2–5 days at the start of the experiment, were used in two experiments with low protein milk replacers (0.10 of total energy as protein) containing isolated soybean protein as the sole source of protein. Experiment 1. Groups of three lambs were given the soybean diet supplemented with DL-methionine (seven levels) in increasing (experiment la) or decreasing amounts (experiment 1b). Dietary periods were each of 3 days. Estimates of minimum intakes of methionine plus cystine, coincident with maximum animal response, based on a 1 day nitrogen balance or on plasma urea nitrogen concentrations, indicated that there was a carry-over effect when methionine was given in decreasing amounts. Experiment 2. An 8 x 8 change-over design was used to minimize carry-over effects. Each lamb was given each diet (seven levels of methionine) for 4 days, in such an order that in the final design each diet was preceded once by every other diet. No carry-over effects were observed. It was concluded that the change-over design could be used to estimate amino acid requirements with fewer animals and with shorter dietary periods than in the conventional balance experiment.

1987 ◽  
Vol 38 (6) ◽  
pp. 1061
Author(s):  
DM Walker ◽  
SJ Al-Ali

Twenty-seven preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were used. Three lambs were sacrificed on day 1 and selected bones taken for analysis. Twenty-four lambs, in groups of three, were bottle-fed on low-phosphorus milk replacers in a 2 x 4 factorial experiment. The sole source of protein in the diets was whole beef blood, supplemented with L-isoleucine and DL-methionine, to supply either 10 or 25% of the total dietary energy as protein. At each protein level the diets were supplemented with CaCO3 to provide four ratios of Ca:P (0.5:1, 1:1, 2:1 and 10:1). The daily intake of gross energy was controlled at 880 kJ-0.73. Faeces and urine were collected separately each day and bulked during the last seven days of the experiment for the estimation of N, Ca and P. Serum Ca and P concentrations were determined at weekly intervals. The lambs were sacrificed at the end of the experimental period of 21 days and selected bones were taken for analysis. The concentrations of bone ash, Ca and P all decreased significantly when compared with values determined at the start of the experiment. The lambs given the high-protein diets showed significantly greater losses of bone ash, Ca and P, and had lower serum P, but higher serum Ca concentrations, than lambs fed on the low-protein milk replacers, irrespective of the dietary Ca:P ratios. Phosphorus excretions during the last seven days of the experiment were as follows: faecal P (day-1); low-protein group (n = 12), 3.1 � 0.5 mg kg-1; high-protein group (n = 11) , 4.1 � 0.5 mg kg-1; all lambs (n = 23), 3.6 � 0.3 mg kg-1. Urinary P (day-1): low-protein group (n = 12), 0.92 � 0.22 mg kg-1; high-protein group (n = 11) , 0.61 � 0.03 mg kg-1; all lambs (n = 23), 0.77 � 0.12 mg kg-1. Faecal and urinary P excretion was unaffected by variation in the dietary Ca:P ratio.


1975 ◽  
Vol 26 (4) ◽  
pp. 673 ◽  
Author(s):  
DM Walker ◽  
RD Kirk

Forty-seven crossbred lambs, aged 2–5 days at the start of the experiment, were used in three experiments. In experiment 1 a supplement of DL-methionine significantly increased the nitrogen balances of lambs given low or medium protein milk replacers based on cows' milk proteins. In experiment 2 the optimum level of supplementation of a low protein diet with DL-methionine was determined. Although the nitrogen balances were significantly increased by the supplement, the actual nitrogen balances at equivalent intakes of gross energy and nitrogen were less than those in experiment 1. The low protein diets in the two experiments differed only in the source of carbohydrate: lactose in cxpcrimcnt 1; lactose + glucose in experiment 2. In the final experiment 24 lambs in a 2 x 2 factorial design were fed on low protein diets containing casein as the source of protein, and lactose or glucose as the sole source of carbohydrate, with or without a supplement of DL-methionine. There was no significant effect of the source of carbohydrate on nitrogen balance.


1979 ◽  
Vol 30 (1) ◽  
pp. 125 ◽  
Author(s):  
R Pelaez ◽  
DM Walker

Preruminant male crossbred lambs, aged about 2 weeks at the start of the experiment, were used. Low protein milk replacers (0.10 of total energy as protein) containing isolated soybean protein (ISP-A or ISP-B) as the sole source of protein were supplemented with mixtures of amino acids. Experiment 1a. Six lambs were each given six isonitrogenous diets in a 6 x 6 change-over design with 4-day dietary periods. The diets contained ISP-B and were supplemented with (1) methionine alone, or methionine plus (2) lysine, (3) isoleucine, (4) threonine, (5) valine or (6) tryptophan. Experiment 1b. Groups of six lambs were given diets containing either ISP-A or ISP-B. Each lamb within a group was given six diets in a 6 x 6 change-over design with 4-day dietary periods. One diet was supplemented with six amino acids (Met, Lys, Isol, Thr, Val and Try) whilst the other five diets had one amino acid (not Met) omitted. Nitrogen balances were determined in experiments 1a and 1b on the last 2 days of each dietary period. Experiment 2. Two groups of four lambs were used in a conventional 12-day nitrogen balance experiment. One group was given the milk replacer containing ISP-B supplemented with the six amino acids used in experiment lb, and the other group the same basal diet supplemented only with Met, Lys and Thr. The addition of single amino acids in addition to methionine did not improve nitrogen balances. Lambs given diets supplemented with Met plus Thr, Val or Try had significantly lower nitrogen balances than those given a supplement of Met alone (experiment 1a). Lambs given diets in which Lys or Thr were omitted from the mixture of six amino acids had Lower nitrogen baIances than any other lambs (experiment 1b). It was concluded that Lys and Thr were equally second limiting in ISP-A and ISP-B at the 0.10 protein energy concentration. The retention of apparently digested nitrogen by lambs given ISP-B supplemented with Met, Lys and Thr (0.669) was significantly higher than that of lambs given ISP-B supplemented with six amino acids (0.590; experiment 2). The mean digestibility coefficient of nitrogen in ISP-B (0.842 ± 0.009) was significantly higher than that in ISP-A (0.764 ± 0.014) and the diets containing ISP-B were more readily accepted by the lambs.


1987 ◽  
Vol 38 (6) ◽  
pp. 1061
Author(s):  
DM Walker ◽  
SJ Al-Ali

Twenty-seven preruminant male crossbred lambs, aged 1-2 days at the start of the experiment, were used. Three lambs were sacrificed on day 1 and selected bones taken for analysis. Twenty-four lambs, in groups of three, were bottle-fed on low-phosphorus milk replacers in a 2 x 4 factorial experiment. The sole source of protein in the diets was whole beef blood, supplemented with L-isoleucine and DL-methionine, to supply either 10 or 25% of the total dietary energy as protein. At each protein level the diets were supplemented with CaCO3 to provide four ratios of Ca:P (0.5:1, 1:1, 2:1 and 10:1). The daily intake of gross energy was controlled at 880 kJ-0.73. Faeces and urine were collected separately each day and bulked during the last seven days of the experiment for the estimation of N, Ca and P. Serum Ca and P concentrations were determined at weekly intervals. The lambs were sacrificed at the end of the experimental period of 21 days and selected bones were taken for analysis. The concentrations of bone ash, Ca and P all decreased significantly when compared with values determined at the start of the experiment. The lambs given the high-protein diets showed significantly greater losses of bone ash, Ca and P, and had lower serum P, but higher serum Ca concentrations, than lambs fed on the low-protein milk replacers, irrespective of the dietary Ca:P ratios. Phosphorus excretions during the last seven days of the experiment were as follows: faecal P (day-1); low-protein group (n = 12), 3.1 � 0.5 mg kg-1; high-protein group (n = 11) , 4.1 � 0.5 mg kg-1; all lambs (n = 23), 3.6 � 0.3 mg kg-1. Urinary P (day-1): low-protein group (n = 12), 0.92 � 0.22 mg kg-1; high-protein group (n = 11) , 0.61 � 0.03 mg kg-1; all lambs (n = 23), 0.77 � 0.12 mg kg-1. Faecal and urinary P excretion was unaffected by variation in the dietary Ca:P ratio.


1972 ◽  
Vol 52 (2) ◽  
pp. 321-328 ◽  
Author(s):  
A. D. L. GORRILL ◽  
J. W. G. NICHOLSON ◽  
H. E. POWER

Two experiments were carried out with Holstein heifer calves to determine the effect of supplying a major portion of the protein in milk replacers by isopropanol-extracted protein concentrate from whole herring (FPC) or a mixture of FPC and soybean protein concentrate (SPC). Milk replacers were compared with whole milk in experiment 1. All calves were abruptly weaned when consuming 0.5 kg starter/day, or by 5 weeks of age. Calf performance was similar when the pre-weaning liquid diet was whole milk, or milk replacers containing either milk protein or 50% of the protein from FPC. Average daily gains to weaning and to 26 weeks of age for all calves were 377 and 692 g/day, respectively. Calves in experiment 2 were fed either an all-milk protein milk replacer or one containing 98% of the protein equally from FPC and SPC. Both milk replacers were fed once daily either six or seven times per week. Calf growth to weaning was lower on the FPC–SPC formula (283 vs. 364 g/day, P < 0.01), but was not significantly different (P < 0.05) to 15 weeks of age (618 vs. 643 g/day). Feeding milk replacer six vs. seven times per week had no significant effect on calf growth. Digestibility coefficients of dry matter, nitrogen, and energy were similar in bull calves fed the all-milk or FPC–SPC protein milk replacers, but retention of absorbed nitrogen was less on the latter diet (54 vs. 45%, P < 0.10).


1971 ◽  
Vol 22 (3) ◽  
pp. 429 ◽  
Author(s):  
KH McIntyre

Urea was infused into sheep both intravenously and intraruminally, and at several increasing rates. The infusions were continuous for at least 6 days for each quantity of urea infused. Three predominantly roughage rations were used. Two of these had the same roughage constituents; both had relatively low protein contents, but one contained starch. The amount of urea nitrogen retained in the body from the urea infused was greatest on the ration containing starch, when the nitrogen balance improved by as much as 4.3 g/day. The concentration of ammonia in the rumen increased linearly with the amount of urea infused by either route of administration, but was much higher in the sheep infused intraruminally. Plasma urea nitrogen concentrations increased linearly with each quantity of urea infused until they reached about 30 mg/100 ml. They increased above this concentration only in the sheep fed on the low protein roughage ration without starch. The results suggest that a renal mechanism for urea excretion may control the plasma urea nitrogen concentration at about 30 mg/100 ml under certain conditions.


1980 ◽  
Vol 31 (1) ◽  
pp. 133 ◽  
Author(s):  
DD Phillips ◽  
DM Walker

Preruminant male crossbred lambs, aged 2-5 days at the start of the experiment, were fed on milk replacers that contained groundnut protein isolate as the sole source of protein, supplemented with graded levels of L-lysine hydrochloride. A series of 6x 6 change-over designs with 4-day dietary periods was used in experiments 1 and 2, and a conventional 14-day nitrogen balance in experiment 3. Estimates were made of the minimum intake of lysine coincident with the maximum animal response (MIMR)-measured as maximum nitrogen balance (NB) or minimum plasma urea nitrogen (PUN) concentration. In experiment 1 three diets with different protein concentrations (0.11, 0.18 and 0.25 of total energy as protein) were compared at a controlled intake of gross energy (0.88 MJ/day per kg0.73). At each protein concentration the response to six graded levels of L-lysine hydrochloride was measured. In experiment 2 a diet of constant protein energy concentration (0.25) was offered at three different intakes of energy (0.63, 0.88 and 1.13 MJ/day per kg0 73). At each level of energy intake the response to six graded levels of L-lysine hydrochloride was measured. In experiment 3 a milk replacer containing 0.25 protein energy was offered at a constant intake of 0.88 MJ gross energy/day per kg0 73 and, as in the previous experiments, the response to SIX graded levels of L-lysine hydrochloride was measured. The MIMR for lysine (expressed as a percentage of dietary protein) decreased curvilinearly with an increase in protein concentration, but was unaffected by an increase in the intake of energy. Estimates based on PUN were similar to those based on NB, but the errors associated with the estimates were greater at the lowest protein concentration in experiment 1 and at the lowest intake of energy in experiment 2. Estimates of MIMR in experiments 1 and 3 were in close agreement.


1978 ◽  
Vol 29 (1) ◽  
pp. 133 ◽  
Author(s):  
MJ Gibney ◽  
DM Walker

Twenty-one male crossbred lambs, aged 2–5 days at the start of the experiments, were used. Experiment I. Groups of three lambs were each given one of three low protein diets (0.10 of the total energy as protein) based on isolated soybean protein. Carbohydrate was omitted from one diet, but in the other two it was added at the expense of fat to provide 0.10 or 0.25 of the total dietary energy. In lambs given the carbohydrate-free diet there was a significant reduction in nitrogen balance, in the retention of the apparently digested nitrogen, in liveweight gain and in plasma glucose levels, but a significant increase in plasma urea nitrogen and in the urinary excretion of nitrogen, urea, ammonia, sodium and potassium. The dry matter content of the faeces of lambs given the diet containing 0.10 carbohydrate (0.450) was significantly higher than that of lambs given the 0.25 carbohydrate diet (0.294). There were no other significant differences in performance between these two groups. Experiment 2. Twelve lambs were given diets based on casein, supplemented with DL-methionine, in which protein supplied 0.100, 0–175 or 0.250 of the total gross energy and, at each protein level, carbohydrate supplied 0.025,0.050, 0.100 or 0.200. There was a significant linear increase in liveweight gain, nitrogen balance and apparently digested nitrogen retained as the carbohydrate concentration at each protein level was increased, and a highly significant effect of the level of dietary protein on all parameters measured. It was concluded that the beneficial effect of carbohydrate on nitrogen balance and liveweight gain is of sufficient consequence to warrant the highest inclusion of carbohydrate in milk replacers for lambs that is compatible with the absence of diarrhoea.


1975 ◽  
Vol 26 (6) ◽  
pp. 1037 ◽  
Author(s):  
DM Walker ◽  
RD Kirk

Preruminant male crossbred lambs, aged 2–5 days at the start of the experiment, were used in five experiments with low protein milk replacers (0.10 of total energy as protein). Experiment 1. A diet with isolated soya bean protein (ISP) as the sole source of protein was supplemented with different amounts of DL-methionine. The ISP contained 1.06 g methionine (M) and 1.04 g cystine (C) per 16 g nitrogen (equivalent to 9.1 mg M + C per 100 kJ diet). Maximum nitrogen balance was achieved when the M + C concentration was 15.3 ? 3.7 mg per 100 kJ (equivalent to 3.8 g M + C per 16 g nitrogen). Experiment 2. The ISP diet (plus DL-methionine), was supplemented with L-valine, or L-threonine, or L-isoleucine, or L-lysine monohydrochloride, or a mixture of essential amino acids, to raise their concentration in rsp to those in whole egg proteins (g per 16 g nitrogen). There was no significant improvement in nitrogen balance as aresult of adding amino acids other than DL-methionine. Experiment 3. The ISP diet was supplemented with either DL-methionine (2.4 and 14.8 mg/100 kJ), or L-methionine (2.4 and 1 4 8 mg/100 kJ), or methionine hydroxy analogue (MHA) (14.8 mg/100 kJ), or L-cystine (14 8 mg/100 kJ). Nitrogen balances were determined. It was concluded that the Dand L-isomers of methionine had similar biological activities when used to supplement ISP, and that MHA was as effective as DL-methionine. There was no significant increase in nitrogen balance with the L-cystine supplement. Experiment 4. The ISP diet (plus DL-methionine) was given to three lambs continuously for 33 days. There was no significant change in nitrogen balance with increasing age. Experiment 5. The ISP diet (diet A) and a diet of equivalent protein content based on cows' milk proteins (diet B) were supplemented with DL-methionine and given to groups of lambs over a wide range of intakes of gross energy (GE). The maximum intake of GE by lambs given the ISP diet ad libitum was 1147 kJ/day per kg0.73, an intake far lower than that which would have been taken by lambs given the cows' milk diet ad libitum. The apparent digestibilities of nitrogen and DM in diet A were significantly lower than those in diet B and, at the mean intake of apparently digested nitrogen of 538 mg/day per kg0.73, there were significant differences in the nitrogen balances: the values were 362 and 255 mg nitrogen/day per for the cows' milk and ISP diets respectively.


1982 ◽  
Vol 33 (1) ◽  
pp. 117
Author(s):  
NM Malouf ◽  
DM Walker

Preruminant male crossbred lambs, aged 2-5 days at the start of the experiment, were fed on milk replacers containing a soybean protein concentrate (as the sole source of protein) to supply 25 % of the total dietary energy as protein. The minimum intake of methionine plus cystine (M+C) that was coincident with maximum nitrogen balance was estimated (mean�s.e.) at 38.5�1.8 mg/100 kJ diet (equivalent to 3.6�0.2 g sulfur amino acids/16 g nitrogen). When the concentration of M+C was raised to this level by supplementation with DL-methionine, the addition of choline chloride, in amounts to give final concentrations varying from approximately one-seventh up to twice the concentration in cows' milk, did not affect nitrogen balance. The maximum replacement value of cystine for methionine (as judged by the effect on nitrogen balance), in milk replacers adequately supplen~ented with choline chloride and sulfur amino acids, was 47% on a weight basis, or 52% when calculated on the basis of moles of sulfur.


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