ABSTRACT
Measures of psychological maturity based on personal strivings (R. A. Emmons, 1989) were administered to 108 adults aged 17-82. On the basis of organismic-theoretical assumptions regarding maturity, age was hypothesized to be positively associated with K. M. Sheldon and T. Kasser's (1995, 1998) two goal-based measures of personality integration. E. Erikson's (1963) assumptions regarding maturity were the basis for the hypothesis that older people would tend to list more strivings concerning generativity and ego integrity and fewer strivings concerning identity and intimacy. Finally, on the basis of past research findings, maturity and age were hypothesized to be positively associated with subjective well-being. Results supported these hypotheses and also showed that measured maturity mediated the relationship between age and well-being. Thus, older individuals may indeed be more psychologically mature than younger people and may be happier as a result.
Subject(s)
Aging/psychology , Personality Development , Adolescent , Adult , Affect , Age Factors , Aged , Aged, 80 and over , Cohort Studies , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Personal Satisfaction , Self Concept , Surveys and QuestionnairesABSTRACT
Three studies compared 10 candidate psychological needs in an attempt to determine which are truly most fundamental for humans. Participants described "most satisfying events" within their lives and then rated the salience of each of the 10 candidate needs within these events. Supporting self-determination theory postulates (Ryan & Deci, 2000)--autonomy, competence, and relatedness, were consistently among the top 4 needs, in terms of both their salience and their association with event-related affect. Self-esteem was also important, whereas self-actualization or meaning, physical thriving, popularity or influence, and money-luxury were less important. This basic pattern emerged within three different time frames and within both U.S. and South Korean samples and also within a final study that asked, "What's unsatisfying about unsatisfying events?" Implications for hierarchical theories of needs are discussed.
Subject(s)
Happiness , Personal Satisfaction , Affect , Cross-Cultural Comparison , Factor Analysis, Statistical , Humans , Korea , Missouri , Psychological Theory , Regression AnalysisABSTRACT
Theoretical work suggests that feelings of insecurity produce materialistic behavior, but most empirical evidence is correlational in nature. We therefore experimentally activated feelings of insecurity by having some subjects write short essays about death (mortality-salience condition). In Study 1, subjects in the mortality-salience condition, compared with subjects who wrote about a neutral topic, had higher financial expectations for themselves 15 years in the future, in terms of both their overall worth and the amount they would be spending on pleasurable items such as clothing and entertainment. Study 2 extended these findings by demonstrating that subjects exposed to death became more greedy and consumed more resources in a forest-management game. Results are discussed with regard to humanistic and terror-management theories of materialism.
Subject(s)
Attitude to Death , Motivation , Socioeconomic Factors , Achievement , Adolescent , Adult , Arousal , Aspirations, Psychological , Fear , Female , Humans , Male , Social ValuesABSTRACT
Self-reported emotional experiences and eating behaviors were studied in college students in an attempt to determine what types of emotional experiences precede and follow binge eating and how specific types of compensatory behaviors modify these experiences. First-year male and female students (N=390) were surveyed for depression, anxiety, health status, life satisfaction, and eating attitudes (EAT-26). Those reporting recurrent binge eating episodes were asked to describe their emotional feelings before and after bingeing and before and after compensatory activities. EAT-26 scores corresponding to scores previously reported for eating disordered patients were found in 9.7% of students. Binge eating was nearly twice as frequent among females (16.4%) as males (8.6%). Among females, positive relationships were found between specific EAT-26 factors scores and both anxiety and depression scores. The emotional antecedents and consequences of binge eating and of compensatory activities were compared in three sub-groups of individuals who reported recurrent bingeing with loss of self-control during binges. The three sub-groups consisted of individuals who reported, 1) bingeing without engaging in compensatory activities, 2) bingeing and compensating by means other than vomiting (fasting, exercising, or use of laxatives or diuretics), and 3) bingeing and compensating by vomiting. Regardless of the type of activity, those individuals who engaged in compensatory activities reported greater negative affect preceding binge episodes than those who did not compensate. In addition, contrary to expectations, negative affect did not decrease, but instead increased significantly, following binge episodes and decreased immediately before and after compensatory activities.
Subject(s)
Affect/physiology , Bulimia/psychology , Adult , Anxiety/psychology , Attitude , Bulimia/epidemiology , Depression/psychology , Emotions , Feeding Behavior/physiology , Female , Health Status Indicators , Humans , Male , Personal Satisfaction , Psychiatric Status Rating ScalesABSTRACT
The effect of recombinant somatotropin (rbST), Synovex (Syn), and their combination (rbST+Syn) on intact male calves was examined in an experiment that lasted an average of 238 d. Holstein-Friesian bull calves were allotted to one of four subtreatments (n = 14/treatment) in a factorial arrangement. There were two levels of rbST (0; rbST) and two levels of the estrogenic growth promoter Synovex (0; Syn). The rbST was administered once every 2 wk as injections of 500 mg of Posilac. Synovex (C and S) was implanted at 90-d intervals. The animals were fed for ad libitum consumption a diet with a metabolizable energy concentration of 11.7 MJ/kg DM and 15% crude protein. The hot carcasses were weighed after the removal of kidney, pelvic, and cod fats, which were weighed separately. The 12th rib cut was saved for analysis. Average daily gain and feed conversion efficiency were increased by rbST treatment by 9% (P < .005) and 10% (P < .016), respectively. There was no significant effect of Syn treatment, nor was there a rbST x Syn interaction. The proportion of the fat of the large depots in the carcass was reduced by 34% (P < .0001) and in the longissimus muscle by 32% (P < .16) owing to the rbST treatment. The plasma concentrations of GH, insulin, and thyroxin were increased by rbST treatment (P < .001, P < .01, and P < .03, respectively). The concentration of IGF-I was not affected. Synovex had no effect on plasma hormone concentration. Plasma essential and nonessential amino acid concentrations were reduced by 14 and 9%, respectively, when rbST was injected. Concentrations of cholesterol and fatty acids in muscle and subcutaneous fat were not affected (P > .072) by the rbST treatment. Synovex increased the monounsaturated fatty acids (MUFA), and the combinaton of Syn with rbST reduced polyunsaturated fatty acid (PUFA) concentration in the longissimus muscle (at the 12th rib). The reduced muscle fat content of the rbST-treated animals was associated with a trend toward an increase in polyunsaturated fatty acids.
Subject(s)
Adipose Tissue/drug effects , Amino Acids/metabolism , Cattle/growth & development , Estradiol/analogs & derivatives , Fatty Acids/analysis , Growth Hormone/pharmacology , Muscle, Skeletal/drug effects , Progesterone/pharmacology , Adipose Tissue/growth & development , Adipose Tissue/metabolism , Animals , Cholesterol/metabolism , Drug Combinations , Estradiol/administration & dosage , Estradiol/pharmacology , Growth Hormone/administration & dosage , Male , Muscle Development , Muscle, Skeletal/growth & development , Muscle, Skeletal/metabolism , Progesterone/administration & dosageABSTRACT
We assessed 28 college students' attitudes toward homosexuals immediately before and 1 week after the presentation of either an article suggesting that male homosexuality has a biological component or a control article. Change in attitude toward homosexuality for subjects exposed to the biological article depended on subjects' memory of the article and on their college major. Subjects undecided in their major and those who scored below average on a memory test of the article's content had the most positive attitude change, while biological science majors and those who scored above average on the memory test became more negative toward homosexuals. The results suggest biological information about homosexuality can have both beneficial and detrimental effects on attitudes toward homosexuals.
Subject(s)
Attitude , Gender Identity , Homosexuality, Male , Adolescent , Adult , Biology , Female , Humans , Male , Surveys and QuestionnairesABSTRACT
A simple method for determining glucose synthesis from radiolabeled precursors in isolated bovine hepatocytes using ion exchange resins is presented. This method allows processing of multiple small volume samples using suspensions of anion and cation exchange resins rather than traditional stacked column separation methods. Hepatocytes were isolated from calf liver by collagenase perfusion of the caudate lobe and were incubated with (14)C-labeled lactate or propionate as gluconeogenic substrates. Glucose synthesis was determined in an aliquot of cell suspension that was vortexed with a slurry of anion exchange (acetate form) resin, followed by a slurry of cation exchange resin. Newly synthesized, labeled glucose was recovered in the supernatant after centrifugation and quantitated by scintillation counting. Using this procedure, more than 98% of the unused labeled precursor was bound to the ion exchange resin and essentially 100% of a labeled glucose tracer was recovered in the supernatant. Pretreatment of hepatocyte suspensions with glucose oxidase was shown to eliminate the accumulation of radioactivity in the supernatant, thus confirming the specificity of this technique for measurement of newly synthesized glucose. This method was sensitive to changes in the rate of hepatic gluconeogenesis that resulted from changes in substrate concentration or the addition of glucagon or fatty acids to the hepatocyte incubations.
Subject(s)
Attitude , Gender Identity , Homosexuality, Male/psychology , Adolescent , Adult , Female , Humans , Male , Personality Assessment , Prejudice , Social IdentificationABSTRACT
The objective of the present study was to determine whether exogenous somatotropin (STH) administration in conjunction with feed restriction could alter the composition of gain in the obese rat. Five-week-old female lean and obese Zucker rats were assigned to the following treatments for 6 wk: ad libitum fed (AL), restricted (approximately 75% of AL lean), and restricted with STH (2 mg STH/day). Growth rate was decreased in restricted groups and was normalized to that of the AL lean group in restricted rats treated with STH. In lean rats, restriction decreased protein accretion. Restriction plus STH treatment decreased lipid accretion but increased protein accretion and body weight gain compared with the AL lean group. As expected, feed restriction reduced body size in obese rats, but carcass lipid was maintained at 44%, a level similar to that of the AL obese rats. Lipid accretion rate was decreased with restriction in obese rats and was further reduced, to a level similar to that of the lean group, in the obese rats that were restricted and treated with STH. Protein accretion was decreased in the restricted obese group but was normalized in those treated with STH to a level similar to that in the AL lean group. Basal rates of lipolysis in isolated adipocytes were not affected by STH. However, STH treatment normalized the responsiveness of cells from the obese rats to stimulation of lipolysis by isoproterenol. The results demonstrate that a combination of caloric restriction and STH was effective in normalizing body weight and composition of gain in the obese Zucker rat.
Subject(s)
Adipose Tissue/metabolism , Body Composition/drug effects , Food Deprivation , Growth Hormone/pharmacology , Obesity/metabolism , Obesity/pathology , Adipose Tissue/pathology , Animals , Energy Intake , Female , Lipid Metabolism , Lipolysis , Liver/enzymology , Liver/pathology , Proteins/metabolism , Rats , Rats, Zucker , Reference Values , Weight Gain/drug effectsABSTRACT
The response to continuous delivery or daily bolus injection of porcine somatotropin (pST) was compared in mature, pituitary-intact female rats (225 g). Growth rate in control rats was approximately 1 g/d over the 14-d study. There was a dose-dependent (0, .4, 1.2, and 3.6 mg of pST/d; P < .001) increase in rate of gain with an interaction (P < .001) of dose and mode of delivery. The slope of the dose-response curve for growth rate was linear on a logarithmic scale for both modes of delivery but was greater for continuous delivery. At the low dose (.4 mg/d) pST stimulated gain (21.7 g/14 d above control, P < .05) when administered by daily injection but failed to stimulate gain (6.0 g/14 d above control, NS) when delivered continuously. At the high dose (3.6 mg/d), gain (above that in control rats) was 49.1 and 79.7 g/14 d for daily and continuous delivery; the two modes were different (P < .05) from each other. Feed intake and liver weights were also stimulated by pST in a dose-dependent manner. The increase in liver size was accompanied by a dose-dependent increase in liver DNA, indicative of an increase in cell number. Increased carcass gain was largely accounted for by increased carcass protein accretion. Rates of carcass lipid accretion were lower than those for protein accretion and were further decreased by pST, particularly by the high dose administered by continuous delivery, where a negative lipid accretion value was observed. Circulating IGF-I was increased by pST (P < .001) but was not affected by the mode of delivery. The results demonstrate that the increased gain observed in mature rats is largely due to lean tissue accretion and is accompanied by an increase in feed intake.
Subject(s)
Body Composition/drug effects , Eating/drug effects , Growth Hormone/pharmacology , Rats, Sprague-Dawley/growth & development , Animals , Body Composition/physiology , Dose-Response Relationship, Drug , Drug Implants , Eating/physiology , Female , Growth Hormone/administration & dosage , Injections/veterinary , Lipid Metabolism , Liver/chemistry , Liver/metabolism , Rats , Species Specificity , Weight Gain/drug effects , Weight Gain/physiologyABSTRACT
Crossbred steers (n = 252, BW = 379 +/- 28 kg) were allotted to 42 pens in a 2 x 3 factorial arrangement of treatments: control or steroid implant (STR; estradiol benzoate+progesterone [three lighter blocks reimplanted on d 84] and trenbolone acetate [reimplanted on d 63]), and either 0, 80, or 160 mg/wk of recombinant bovine somatotropin (bST). Steers were adapted to the finishing diet (12% roughage equivalent, 13% CP) before the start of the experiment and fed for 84 or 119 d. Blood samples were taken on d 0, 14, 28, 56, and 84 for plasma urea N (PUN), serum somatotropin (ST), plasma insulin-like growth factor I (IGF-I), and plasma amino acid assay. Few interactions were noted (P > .1). Gain was increased by both treatments: 1.30 vs 1.66 kg/d for control vs. STR (P < .001) and 1.44, 1.49, and 1.51 kg/d (linear, P = .07) for 0, 80, and 160 mg of bST/wk, respectively. Gain efficiency was also improved: 169 vs 205 g/kg (P < .001) and 177, 189, and 195 g/kg (linear, P < .001), respectively. Average PUN was decreased (P < .001) 29% by STR and decreased 17 and 29% by 80 and 160 mg of bST/wk, respectively (linear, P < .001). Somatotropin decreased mean serum ST compared with controls; STR increased ST 36% compared with controls. Average plasma IGF-I was increased (P < .001) 12% by STR and 13 and 19% (linear, P < .001) by 80 and 160 mg of bST/wk, respectively. Both STR and bST influenced (P < .05) plasma amino acid profiles. Indicators of carcass fatness were decreased linearly (P < .05) by bST; STR implant tended to decrease carcass fatness and increase longissimus muscle area, which was related to carcass weight. The anabolic effects of STR and bST were found to be additive and possibly independent in feedlot steers.
Subject(s)
Anabolic Agents/standards , Cattle/growth & development , Growth Hormone/standards , Amino Acids/blood , Anabolic Agents/pharmacology , Animals , Body Composition/drug effects , Body Composition/physiology , Cattle/metabolism , Crosses, Genetic , Dose-Response Relationship, Drug , Drug Implants , Estradiol/pharmacology , Estradiol/standards , Estrogens/blood , Growth Hormone/blood , Growth Hormone/pharmacology , Injections , Insulin-Like Growth Factor I/analysis , Male , Random Allocation , Trenbolone Acetate/pharmacology , Trenbolone Acetate/standards , Urea/blood , Weight Gain/drug effects , Weight Gain/physiologyABSTRACT
Coherence and congruence-based measures of personality integration were related to a variety of healthy personality characteristics. Functional coherence was defined as occurring when participants' "personal strivings" (R.A. Emmons, 1986) help bring about each other or help bring about higher level goals. Organismic congruence was defined as occurring when participants strive for self-determined reasons or when strivings help bring about intrinsic rather than extrinsic higher level goals. Study 1 found the integration measures were related to each other and to inventory measures of health and well-being. Study 2 showed that these goal integration measures were also related to role system integration and were prospective predictors of daily mood, vitality, and engagement in meaningful as opposed to distracting activities.
Subject(s)
Internal-External Control , Personality Development , Self Concept , Adult , Aspirations, Psychological , Female , Humans , Male , Motivation , Personality AssessmentABSTRACT
Formulated zinc methionyl bST (sometribove, 50, 100, or 150 mg) was administered as a single treatment once every 2 wk or as two equal treatments once/week to evaluate the efficacy of prolonged release delivery of bovine somatotropin (bST) in finishing lambs. Feed conversion during the 6-wk treatment period was improved 9 and 19% in lambs that received treatments once and twice/2 wk, respectively (P < .05), and the responses to differing doses were similar within a dosing frequency (P > .05). Carcass muscle:fat ratio indicators generally were affected in a dose-related manner and were independent of frequency of administration. For example, fat thickness was 17, 30, and 42% lower than control in lambs that received 50, 100, and 150 mg of formulated sometribove/2 wk, respectively (P < .05). Percentages of muscle were higher and of fat were lower with increasing dose of formulated sometribove, but weight of only fat was significantly affected (P < .05). Clinical chemistry indices of metabolic effects of bST (e.g., circulating bST, IGF-I, insulin, glucose, and urinary nitrogen concentrations) were affected in directions similar to those observed with bST administered by daily injection. The results of this study demonstrate the growth performance and carcass composition advantages of a formulation designed to deliver bST over a 2-wk period.
Subject(s)
Body Composition/drug effects , Growth Hormone/analogs & derivatives , Hormones/pharmacology , Meat/standards , Sheep/growth & development , Adipose Tissue/drug effects , Adipose Tissue/growth & development , Analysis of Variance , Animals , Blood Glucose/analysis , Blood Urea Nitrogen , Delayed-Action Preparations , Female , Growth Hormone/administration & dosage , Growth Hormone/pharmacology , Hormones/administration & dosage , Human Growth Hormone , Injections, Subcutaneous/adverse effects , Injections, Subcutaneous/veterinary , Insulin/blood , Insulin-Like Growth Factor I/analysis , Male , Muscle Development , Muscle, Skeletal/drug effects , Muscle, Skeletal/growth & development , Random Allocation , Recombinant Proteins/administration & dosage , Recombinant Proteins/pharmacologyABSTRACT
Four cross-bred beef steers averaging 346 kg were used in a 4 x 4 Latin square design to determine the effect of prolonged-release recombinant bovine somatotropin (rbGH) implants on serum concentrations of somatotropin (GH), insulin-like growth factor-I (IGF-I) and blood urea nitrogen (BUN). Recombinant bGH implants of 0, 40, 80 or 160 mg were administered subcutaneously in the tailhead during the 4 trial periods. Each steer received each treatment starting at 06:00 on day 0 with 21 days between treatments. Jugular vein blood samples were collected on days 0, 1, 2 and 3 (4 day time course for GH, IGF-I and BUN) and every 15 min (GH profile) for 6 h on day 3. Serum baseline GH values were higher (P < 0.10) for the 80 and 160 mg treatments than for the control, and peak amplitude was decreased (P < 0.05) by the 40 and 160 mg treatments. There was a trend (P < 0.11) for fewer GH peaks during the 160 mg treatment. Somatotropin concentrations decreased from day 1 to day 3 (P < 0.05) in a linear manner. Serum IGF-I concentrations increased (P < 0.05) in a linear dose-dependent manner from the 0 mg to the 160 mg treatment. BUN concentrations were not significantly altered by rbGH treatment. Results from this experiment indicate that rbGH implants significantly increase serum IGF-I and GH baseline concentrations while suppressing GH peak amplitude in finishing steers.
Subject(s)
Blood Urea Nitrogen , Cattle/blood , Growth Hormone/blood , Growth Hormone/pharmacology , Insulin-Like Growth Factor I/metabolism , Animals , Drug Implants , Growth Hormone/administration & dosage , Kinetics , Male , Recombinant Proteins/pharmacologyABSTRACT
Effects of porcine somatotropin (pST) on growth and carcass characteristics of Meishan (Ms) and Yorkshire (Y) barrows given 3 mg of pST or saline daily were determined for two end points. First, 26 Ms and 26 Y barrows were treated from 119 d of age until the Y barrows reached 108 kg. Second, another 18 Ms barrows were treated to 108 kg BW. Age- and weight-matched treatments were analyzed. Results for both groups indicated pST effects (P < .05) for feed conversion (+) and intake (-), dressing percentage (-), percentage of carcass fat (-) and protein and water (+), leaf fat (-), backfat (BF) thickness (-), longissimus muscle area (LMA; +), skin thickness (+), muscle firmness and marbling scores (-), organ weights (+), belly (-), clear plate (-), ham (+), and total boneless cuts (BC; +). Somatotropin effects were also present for loin (-) and boneless Boston butt (BBB; +) in the age-matched group and for ADG (+), carcass weight (-), loin (-), jowl (-), and tenderloin (+) in the weight-matched group. Breed effects (P < .05), in favor of Y barrows, in both treatments existed for ADG (+) and feed intake (+), carcass weight (+), dressing percentage (+), LMA (+), skin thickness (-), muscle color and firmness scores (-), muscling score (+), all wholesale cuts (WC; +) except clear plate (age-matched), all trimmed cuts (TC; +) except picnic shoulder (weight-matched), and all BC (+). Breed effects, in favor of Y barrows, were also determined for carcass length (+), percentage of carcass ash (-), leaf fat (+), average BF thickness (+), and heart (-) and liver (-) weights in age-matched animals and percentage of carcass fat (-), protein (+), water (+), leaf fat (-), 10th rib, average, and P2 BF thicknesses (-), marbling score (-), femur length (-), and liver weights (+) in weight-matched animals. A higher response to pST (P < .05) was determined in Ms barrows than in Y barrows for percentage of carcass protein (+), liver (+), and heart (+) in the age-matched treatment and 10th rib BF thickness (-) and heart weight (+) in the weight-matched treatment. Yorkshire barrows treated with pST had more improved values for color score (+; age-matched) and BBB (+; weight-matched).
Subject(s)
Body Composition/drug effects , Growth Hormone/pharmacology , Meat/standards , Swine/growth & development , Adipose Tissue/drug effects , Adipose Tissue/growth & development , Analysis of Variance , Animals , Breeding , Eating , Male , Muscle Development , Muscles/drug effects , Random Allocation , Recombinant Proteins/pharmacologyABSTRACT
Bovine placental lactogen (PL) is a partial somatotropin agonist in the cow and decreases urea nitrogen, indicating increased nitrogen retention. In the present study, the somatogenic effects of bovine PL (bPL; 4 and 8 mg/d) were compared with those of bovine somatotropin (bST; 4 and 8 mg/d) in finishing lambs. Measures of comparison included growth performance, carcass composition, and growth-related clinical chemistry traits. Although feed efficiency during the first 3 wk of treatment with bPL was improved by 14% (P < .05), feed efficiency for the full 6-wk treatment period did not differ from that of control lambs. Responsiveness to bPL may have been attenuated by high titer antibodies present after 2 wk of treatment. However, bPL also did not influence growth-related clinical chemistry traits during short-term (7 d) treatment, strongly suggesting that bPL was ineffective in finishing lambs at the doses tested. In contrast, bST improved 6-wk feed efficiency by an average of 17% (P < .05) and decreased feed intake by an average of 12% (P < .05). In addition, measures of carcass composition including longissimus muscle area, specific gravity of the rack, kidney and pelvic fat, and fat thickness demonstrated that bST, but not bPL, treatment decreased carcass fatness and increased carcass leanness. Treatment with bST, but not with bPL, affected IGF-I, insulin, glucose, and urea nitrogen in a dose-related manner. Thus, daily injections of bPL did not affect either performance or carcass quality, whereas performance and carcass responses of finishing lambs to bST were consistent with those reported by others.
Subject(s)
Growth Hormone/pharmacology , Placental Lactogen/pharmacology , Sheep/growth & development , Adipose Tissue/drug effects , Adipose Tissue/growth & development , Animals , Blood Glucose/analysis , Blood Urea Nitrogen , Body Composition/drug effects , Dose-Response Relationship, Drug , Eating/drug effects , Female , Growth Hormone/blood , Insulin/blood , Insulin-Like Growth Factor I/analysis , Male , Meat/standards , Muscle Development , Muscles/drug effects , Placental Lactogen/blood , Random Allocation , Recombinant Proteins/pharmacology , Sheep/blood , Weight Gain/drug effectsABSTRACT
Aspiring for financial success is an important aspect of capitalist cultures. Three studies examine the hypothesis that values and expectancies for wealth and money are negatively associated with adjustment and well-being when they are more central to an individual than other self-relevant values and expectancies. Studies 1 and 2 use 2 methods to show that the relative centrality of money-related values and expectancies is negatively related to college students' well-being and mental health. Study 3, using a heterogeneous noncollege sample, extends these findings by showing that a high centrality of aspirations for financial success is associated with interview ratings of lower global adjustment and social productivity and more behavioral disorders. Discussion is focused on the deleterious consequences of materialistic world views and the need to examine differential effects of content regarding goals and values.
Subject(s)
Aspirations, Psychological , Life Style , Mental Health , Stress, Psychological/etiology , Adult , Female , Goals , Humans , Male , Surveys and Questionnaires , United StatesABSTRACT
The variation in growth and carcass composition responses of lambs to somatotropin (ST) treatment may depend on the source of ST used as well as on other experimental conditions. In the present experiment, growth, carcass composition, and clinical chemistry responses to recombinantly produced ovine ST (oST) and two bovine ST (N-methionyl-bST[M-bST] and N-alanyl-bST[A-bST] were compared. Lambs weighing 42 kg were assigned to treatment groups of control (no injection) or 4 mg/d of M-bST, A-bST, or oST administered by s.c. injection for 6 wk. Growth rate was increased by an average of 30% and feed efficiency was improved by an average of 22% by ST treatment compared with control, and responses did not differ among ST. The IGF-I, insulin, and glucose concentrations were increased by 107, 700, and 53% compared with control, respectively, and did not differ among ST treatment groups. Urea nitrogen responses to A-bST and oST were transiently greater than those to M-bST. Although quality grade was not affected by treatment, an average .8-kg increase in weight of retail cuts was calculated from yield grade. Carcasses of ST-treated lambs were calculated to have 1.3 kg more muscle and 1.9 kg less fat. Although fat and muscle were affected more by oST than by M-bST on a percentage basis, they did not differ among treatment groups on a total weight basis. Thus, both bST variants and oST improved growth performance and carcass leanness. Decreased responses of some carcass variables to M-bST treatment may have been related to the presence of antibodies that were indicated by an increased number of positive responders in a relative bST binding assay.
Subject(s)
Body Composition/drug effects , Growth Hormone/pharmacology , Sheep/growth & development , Weight Gain/drug effects , Adipose Tissue/drug effects , Adipose Tissue/growth & development , Animals , Blood Glucose/analysis , Blood Urea Nitrogen , Cattle , Eating/drug effects , Female , Insulin/blood , Insulin-Like Growth Factor I/analysis , Male , Meat/standards , Muscle Development , Muscles/drug effects , Random Allocation , Recombinant Proteins/pharmacology , Regression Analysis , Sheep/anatomy & histology , Sheep/bloodABSTRACT
Ninety pigs were used to investigate the efficacy of long-term implants of porcine somatotropin (pST) in improving growth, feed:gain ratio, and carcass characteristics in pigs at three dose levels (0-, 100-, and 200-mg pST implant) from 71 to 99 kg live weight. The use of long-term implants did not alter (P > .05) growth rate. Administration of the 200-mg pST implant resulted in a 15% reduction in feed consumption, and this reduction was significant (P < .05). The feed:gain ratio was improved (P < .05) in pigs that received the 200- compared with 0-mg pST implant (3.2 vs 2.62 of kg feed/kg of gain). In pigs that received the 200- or 100-mg pST implant, there was a reduction (P < .05) in carcass weight; however, carcass length was similar (P > .05) regardless of pST treatment. Administration of the 200-mg pST implant resulted in 25 and 38% reductions (P < .05) in last rib fat and leaf fat compared with the 0-mg pST implant. The weights of kidneys and head were increased by the pST administration. The weights of wholesale cuts were not affected by the administration of the pST implant. However, separable skin and fat from the ham, loin, and picnic were lower (P < .05) in pigs that received the 200-mg pST than in pigs that received the 0-mg pST implant. Meat color and structure were similar across pST treatments, indicating that the use of long-term pST implants was not detrimental to meat quality.(ABSTRACT TRUNCATED AT 250 WORDS)