The effects of a combined implant of trenbolone acetate and oestradiol-17/3 on protein and energy metabolism in growing beef steers

Gerald Lobley, A CONNELL, G S MOLLISON, A BREWER, C I HARRIS, Vivien Buchan, H GALBRAITH

Research output: Contribution to journalArticle

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Abstract

combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17,8 (OE) have been examined in Hereford x Friesian beef steers (280-520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions.
2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.54.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy:total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals.
3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [ I-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week +5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and +5 (P c 0.05) compared with control animals. The ratio, protein depositi0n:protein synthesis was 0.05 for control animals but 0.08410 for steroid-treated animals after implantation.
4. There was a slight decrease in urinary W-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention.
5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids.
6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding
of the role of the endogenous sex hormones.
Original languageEnglish
Pages (from-to)681-694
Number of pages14
JournalBritish Journal of Nutrition
Volume54
Issue number3
DOIs
Publication statusPublished - 1985

Cite this

The effects of a combined implant of trenbolone acetate and oestradiol-17/3 on protein and energy metabolism in growing beef steers. / Lobley, Gerald; CONNELL, A ; MOLLISON, G S ; BREWER, A ; HARRIS, C I ; Buchan, Vivien; GALBRAITH, H .

In: British Journal of Nutrition, Vol. 54, No. 3, 1985, p. 681-694.

Research output: Contribution to journalArticle

Lobley, Gerald ; CONNELL, A ; MOLLISON, G S ; BREWER, A ; HARRIS, C I ; Buchan, Vivien ; GALBRAITH, H . / The effects of a combined implant of trenbolone acetate and oestradiol-17/3 on protein and energy metabolism in growing beef steers. In: British Journal of Nutrition. 1985 ; Vol. 54, No. 3. pp. 681-694.
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abstract = "combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17,8 (OE) have been examined in Hereford x Friesian beef steers (280-520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions. 2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.54.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy:total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals. 3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [ I-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week +5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and +5 (P c 0.05) compared with control animals. The ratio, protein depositi0n:protein synthesis was 0.05 for control animals but 0.08410 for steroid-treated animals after implantation. 4. There was a slight decrease in urinary W-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention. 5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids. 6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding of the role of the endogenous sex hormones.",
author = "Gerald Lobley and A CONNELL and MOLLISON, {G S} and A BREWER and HARRIS, {C I} and Vivien Buchan and H GALBRAITH",
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T1 - The effects of a combined implant of trenbolone acetate and oestradiol-17/3 on protein and energy metabolism in growing beef steers

AU - Lobley, Gerald

AU - CONNELL, A

AU - MOLLISON, G S

AU - BREWER, A

AU - HARRIS, C I

AU - Buchan, Vivien

AU - GALBRAITH, H

PY - 1985

Y1 - 1985

N2 - combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17,8 (OE) have been examined in Hereford x Friesian beef steers (280-520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions. 2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.54.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy:total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals. 3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [ I-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week +5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and +5 (P c 0.05) compared with control animals. The ratio, protein depositi0n:protein synthesis was 0.05 for control animals but 0.08410 for steroid-treated animals after implantation. 4. There was a slight decrease in urinary W-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention. 5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids. 6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding of the role of the endogenous sex hormones.

AB - combined implant of 140 mg trenbolone acetate (TBA)+20 mg oestradiol-17,8 (OE) have been examined in Hereford x Friesian beef steers (280-520 kg). Comparisons were made both with the same animals before implantation and with untreated control animals maintained under similar physiological and nutritional conditions. 2. Over a 10 week period the implanted steers showed an improvement in rate of live-weight gain (LWG) of 0.54.6 with an even greater proportional increase in N retention compared with control animals. Total energy retention was unaffected and thus the ratio, protein energy:total energy gain was 0.43 for implanted steers compared with 0.26 for untreated animals. 3. Estimates of protein synthesis and protein oxidation were obtained from the specific radioactivities of blood free-leucine and exhaled carbon dioxide during continuous infusions of [ I-14C]leucine. Whole-body protein synthesis, based on metabolic size, and amino acid fractional oxidation remained similar for control steers throughout the experiment. Steroid-treated steers showed a slight decline in synthesis which was significant (P < 0.05) at week +5 post-implant while amino acid oxidation was significantly lower at weeks +2 (P < 0.01) and +5 (P c 0.05) compared with control animals. The ratio, protein depositi0n:protein synthesis was 0.05 for control animals but 0.08410 for steroid-treated animals after implantation. 4. There was a slight decrease in urinary W-methylhistidine elimination after implantation which suggested that muscle protein degradation may be reduced although the estimated decrease was insufficient to account for the total improvement in growth rate and N retention. 5. The results suggest that for both control and treated steers, less than 0.5 of total urine N elimination was derived directly from tissue catabolism of protein and amino acids. 6. The combined action of the exogenous steroids in the promotion of protein gain, primarily through a decrease in total protein degradation with little alteration of total energy retention, is compared with present understanding of the role of the endogenous sex hormones.

U2 - 10.1079/BJN19850154

DO - 10.1079/BJN19850154

M3 - Article

VL - 54

SP - 681

EP - 694

JO - British Journal of Nutrition

JF - British Journal of Nutrition

SN - 0007-1145

IS - 3

ER -