Gas chromatographic-mass spectrometric determination of natural profiles of androgens, progestogens, and glucocorticoids in muscle tissue of male cattle

 A rapid and economical method was developed for the simultaneous determination of androgens, progestogens, and glucocorticoids and their precursors and metabolites in meat. Steroids were isolated with liquid extraction followed by C₁₈-solid-phase extraction (C₁₈-SPE). Corticoids were separated from the less polar steroids by Si-SPE. The non-polar steroids required additional purification by filtration through an NH₂ cartridge. The fractions were combined and derivatized with a universally applicable trimethylsilylation of both hydroxyl and keto groups. Determination was performed with gas chromatography-mass selective detection (determination limits: 0.02–0.1 μg/kg). Hormone profiles of 15 muscle tissue samples of both bulls and steers were analysed. Beef from bulls contained higher concentrations of testosterone and epitestosterone (P<0.001), 11-deoxycorticosterone (P<0.01), androstenedione (P<0.05) and cortisone (P<0.05), and significantly lower proportions of cortisol (P<0.001) than beef from steers. Received: 21 April 1998     

Profiles of steroid hormones in beef from steers implanted with Synovex-S (estradiol benzoate and progesterone) in comparison to control steers

 Profiles of steroid hormones (androgens, estrogens, progestogens and corticoids), their precursors and metabolites were analyzed in nine beef samples obtained from steers which had received the anabolic implant Synovex-S (200 mg progesterone plus 20 mg estradiol benzoate) and in nine samples from control steers. Analysis of phenolic steroids was performed by enzyme immunoassay after separation by HPLC. Neutral steroids were determined by GC-MS. Concentrations of the hormones progesterone and 17β-estradiol, of their precursors and metabolites (pregnenolone, 17α-hydroxyprogesterone, dehydroepiandrosterone, androstenedione, epitestosterone, α-androsterone, 17α-estradiol, and estrone) and of the corticosteroids cortisone and hydrocortisone did not differ significantly between treatments (P>0.05) but the ratio of 17β-estradiol to its metabolites and the cortisone/hydrocortisone ratio were significantly higher in beef from treated steers (P<0.01). Concentrations of testosterone and 5α-dihydrotestosterone were below the determination limits (10 ng/kg and 20 ng/kg, respectively) in both treated and control steers.     

Influence of sampling on steroid hormone patterns of beef from bulls and steers

Three different muscles (Longissimus dorsi, Semitendinosus, Extensor carpi ulnaris) of bulls and steers, which represent different parts of the carcass and which have differing properties (function, proportions of fat and connective tissue), were analysed with GC-MS for their contents of testosterone, cortisol, cortisone, pregnenolone, dehydroepiandrosterone, progesterone, hydroxyprogesterone, androstenedione, dihydrotestosterone, epitestosterone and androsterone. No difference in the hormone patterns could be detected between the three muscles. However, the enrichment of beef samples with inter- and intramuscular fat decreased the levels of the polar corticosteroids, whereas the levels of lipophilic steroids were increased. The patterns of the lipophilic sex steroids, their precursors and metabolites, which can be used to determine the sexual origin of beef and which might prove useful in evaluating residues of administered steroid hormones, seem to be less affected by the beef sample's fat content, however.     

Sex steroid levels in urine of cattle of different ages: evaluation of abuse control procedures

Levels of several natural urinary steroids have been determined in the urine of a large number of animals of different cattle categories in the context of steroid abuse in beef production. Bovine animals of different breeds, sex and age included in the Slovene national residue detection plan for steroid abuse were studied. Urine from 120 males and 174 females was analysed. Urinary boldenone, boldione, androstenedione, equiline, medroxyprogesterone, medroxyprogesterone acetate, melengestrol acetate, progesterone, stanozolol, trenbolone, trenbolone acetate, 17α-ethinylestradiol, 17α-methyltestosterone, epitestosterone, 17β-estradiol, testosterone, and nandrolone were determined by LC-MS/MS. Epitestosterone was found in all bulls; while the proportion of animals containing testosterone and androstenedione increased with age. Testosterone was not detected in bulls less than 5 months of age. Epitestosterone levels, however, were not age dependent. The ratio of testosterone to epitestosterone thus increased with age, from 0.13 ± 0.09 at 1–7 months to 0.42 ± 0.10 at 25–38 months. It was significantly (p < 0.01) higher in bulls above 13 months than in younger animals. In contrast to males, no urinary testosterone was found in females, whereas epitestosterone, androstenedione, progesterone and estradiol were present. The proportion of animals of various age groups in which epitestosterone was detected ranged from 68% to 100%, but the differences were not significant. The presence of both estradiol and progesterone in the same sample was not observed in any animal. The results of this study could be helpful in determining physiological urinary steroid levels in order to provide a baseline for the control of steroid abuse in beef production.     

The behaviour and blood profile of bulls which produce dark cutting meat

Thirty British Friesian bulls (12 months old), in groups of 6 or 12, were mixed with unfamiliar animals for 16 h preslaughter. Before and during mixing, blood samples were collected and behaviour was monitored. The ultimate pH (pHu) was measured in the m. Longissimus dorsi (LD) 24 h after slaughter. Thirteen carcasses were dark cutting (DC, pHu≧6) and 17 were normal (pHu<6). DC carcasses came from animals which exhibited over twice the total number of agonistic interactions (P<0.001) and showed more dominant behaviour (P<0.001) than animals producing normal carcasses. There was no difference in the blood profile of DC and normal bulls before mixing. However, DC bulls had higher levels of creatine phosphokinase (P<0.001), free fatty acids (P<0.001) and β-hydroxybutyrate (P<0.01) in the blood samples collected after mixing. Overall, pHu was correlated with total activity (r=0.71, P<0.001) and dominance scores (r=0.70, P<0.001). The conclusion is that the cause of DC in mixed groups of bulls is primarily behavioural. Muscle glycogen stores are depleted when blood-borne metabolites are inadequate to fuel the intense or prolonged muscular activity associated with agonistic behaviour.     

Relationship between pre-slaughter stress responsiveness and beef quality in three cattle breeds

The relationship between stress responsiveness and beef quality of 40 Nguni, 30 Bonsmara and 30 Angus steers was determined. The L^* values, pHu, cooking loss (CL) and Warner-Bratzler shear force (WBSF) were determined. Catecholamine levels were determined from urine samples collected at slaughter. Bonsmara steers had the highest (P < 0.05) levels of catecholamines with respective epinephrine, norepinephrine and dopamine concentrations of 10.8, 9.7 and 14.8 nmol/mmol. Nguni steers had the lowest (P < 0.05) levels of catecholamines, with respective catecholamine concentrations of 5.1, 4.3 and 4.0 nmol/mmol. In the Nguni steers, there were significant (P < 0.05) correlations between catecholamines and L^* and between dopamine and tenderness in meat aged for two days (WBSF2). In the Bonsmara, dopamine was correlated (P < 0.05) pHu, WBSF2 and CL. No significant correlations were found in the Angus. Therefore the relationship between stress responsiveness and certain beef quality traits may not be similar in different breeds.     

Composition and quality differences between the longissimus and infraspinatus muscles for several groups of pasture-finished cattle

Samples of longissimus (LT) and infraspinatus (IS) muscles from five contrasting groups of pasture-finished cattle (n = 7/group) were assessed for quality and composition characteristics in order to determine whether features of pasture-finished beef reported previously apply across different muscles and different classes of cattle. The cattle were not raised together or slaughtered at the same time. Wagyu-cross steers had the highest intramuscular fat levels, particularly in the LT, followed by Angus steers, Charolais-cross steers and Belgian Blue-cross steers, with the lowest levels for Friesian bulls. Relative to the LT, the IS muscle had longer sarcomeres, higher cooking losses, higher concentrations of vitamin E, and lower myofibrillar fragmentation indexes, while its ultimate pH was slightly higher but less variable. Beef from Wagyu-cross steers had the highest chroma values and the lowest shear values, while Friesian bull beef was darkest and least tender. Intramuscular fatty acid composition and concentrations of bioactive compounds such as coenzyme Q₁₀ and carnosine, were similar to those reported previously for cattle finished on New Zealand pastures although taurine levels were lower. Generally concentrations of bioactive compounds differed more between muscles and groups than between cattle finished on pasture or grain as reported previously.     

Effect of vitamin A restriction on performance and meat quality in finishing Holstein bulls and steers

Twenty-four Holstein steers and 23 Holstein bulls (initial body weight = 252 ± 3.5 kg and age = 187 ± 7.5 d) were randomly allocated to 4 treatments arranged in a 2 × 2 factorial design with gender (bulls vs steers) and vitamin A supplementation (either restricted at 1.3 × 1000 IU/kg, VAR, or supplemented at 4.6 × 1000 IU/kg, CTR) to evaluate the effect of vitamin A restriction on performance, carcass and meat quality traits of Holstein steers and bulls. Intramuscular fat was less (P < 0.01) in bulls than in steers, and tended (P = 0.09) to be greater in VAR than in CTR animals. Oxidative stability tended (P = 0.09) to be greater in meat from VAR than from CTR animals at 21 d of ageing. Vitamin A restriction in Holstein bulls does not achieve the same intramuscular fat levels obtained with castration.     

Colour of subcutaneous adipose tissue and M. longissimus dorsi of high index dairy and beef×dairy cattle slaughtered at two liveweights as bulls and steers

The objectives of this study were (a) to compare muscle and adipose tissue colour of male progeny of two strains of high genetic merit Friesian cows (New Zealand [NZF] and Irish [DAF]) with those of beef (Belgian Blue)×dairy (Holstein-Friesian) [BBHF] male progeny; (b) to compare bulls and steers (gender) of these genotypes and (c) to examine the effects of slaughter weight (SW) on these quality traits. Bulls (n=48) and steers (n=48) of the three genotypes were grown to nominal target liveweights of 550 kg (light) and 630 kg (heavy). Adipose tissue from the NZF genotype was more yellow (P<0.05) than from DAF or BBHF, regardless of gender or SW. For longissimus dorsi (LD) pH, bulls and heavy animals had higher pH (P<0.05) than steers or light animals, respectively, while NZF and BBHF bulls had higher pH than steers. LD muscle from the BBHF genotype had lighter colour (P<0.05) and lower haem pigments (P<0.01) than NZF or DAF progeny. There was no difference in muscle `L' value between light bulls and steers but heavy bulls had darker muscle than heavy steers. There was an interaction between genotype, gender and SW for LD redness. Thus, NZF animals were most red when slaughtered as light or heavy bulls, but there were no differences between genotypes slaughtered as light or heavy steers. These data demonstrate differences in colour of beef, especially from progeny of NZF, which produced the most yellow adipose tissue and the most red muscle tissue.     

Natural occurrence of steroid hormones in food

The natural occurrence of the sex steroid hormones progesterone, testosterone, 17β-estradiol and estrone in food was investigated in a survey of the German market basket. The main metabolic precursors, intermediates and metabolites (pregnenolone, androstenedione, hydroxyprogesterone, dehydroepiandrosterone (DHEA), dihydrotestosterone, androsterone, 17α-estradiol and estriol) were also included in the investigation. Particular attention was paid to DHEA, which is said to have anti-aging properties. Analysis was carried out by gas chromato-graphy-mass spectrometry (GC-MS). The steroid patterns of pork, meat products, fish and poultry resemble those known for beef. Milk and milk products reflect the hormone profile of female cattle with high amounts of progesterone, which accumulates with increasing milk fat content. Milk products supply about 60–80% of ingested female sex steroids. Eggs are a considerable source of any of the investigated steroids and contribute to the nutritional hormone intake in the same order as meat and fish (10–20%). In vegetable food no estrogens could be detected. Plants supply testosterone in the same order as meat and milk products (20–40%) though. They contain considerable amounts of hormone precursors as well (contribution to DHEA supply: about 80%). In comparison to the human daily production of steroid hormones the nutritional supply (about 10 μgd⁻¹ progesterone, 0.05 μg d⁻¹ testosterone, 0.1 μg d⁻¹ estrogens, 0.5 μg d⁻¹ DHEA) is insignificant.     

Effects on performance and carcass and meat quality attributes following immunocastration with the gonadotropin releasing factor vaccine Bopriva or surgical castration of Bos indicus bulls raised on pasture in Brazil

Bos indicus bulls 20 months of age grazed on pasture in Minas Gerais, Brazil either received 2 doses of the GnRF vaccine Bopriva at d0 and d91 (group IC, n = 144) or were surgically castrated on d91 (group SC, n = 144). Slaughter on d280, was 27 weeks after castration. Adverse safety issues in 8% of group SC bulls following surgery contrasted with 0% in group IC bulls. At d105 testosterone levels were suppressed to similar levels in both groups. Importantly, group IC bulls had higher live weight, hot carcass weight, ADG (P < 0.005) and dressing percentage (P < 0.0001) compared to group SC animals. There were no negative effects on carcass or meat quality traits, thus immunocastration was concluded to offer a safe and effective method that provides production gains, and improves animal welfare in Bos indicus beef bulls without impacting meat and carcass quality.     

Interrelationships between meat quality traits, texture measurements and physicochemical characteristics of M. rectus abdominis from Charolais heifers

Ninety-nine Charolais heifers were used to study the variability of meat quality traits in relation to the physicochemical characteristics of M. rectus abdominis. The heifers of the same trade class were slaughtered at 33 months of age (±4 months) and 381 kg carcass weight (±31 kg). Muscle and bone development scores were evaluated before slaughter. Carcass weight, slaughter age and life average daily gain were recorded. Shear force measurements and meat quality traits were evaluated after 14 days of aging. Some physicochemical characteristics were measured 24 h post-slaughter.Tenderness was correlated with slaughter age (r = −0.31), bone development (r = −0.22) and life average daily gain (r = +0.37). Tenderness was significantly related to total collagen content (r = −0.24), lipid content (r = +0.27) and I myosin heavy chain proportion (r = +0.24). Juiciness was positively correlated with lipid content (r = +0.31) and I myosin heavy chain proportion (r = +0.20). Flavor intensity was correlated with lipid content (r = +0.26) and mean fiber area (r = +0.24). Shear force was correlated with total collagen, lipid and 27K proteasome sub-unit contents. Taking animal characteristics and muscle properties together in a multiple regression analysis increased the explained tenderness variability to 33%. The independent variables listed in order of importance were life average daily gain, total collagen content, bone development, lipid content, I myosin heavy chain isoform proportion, shear force of broiled meat and slaughter age.     

Genetic and Environmental Variation for Seed Yield,Protein, Lipid and Amino Acid Composition in Cowpea (Vigna unguiculata (L) Walp)

The genetic and environmental variability for seed yield (kg ha^-1), protein content (g kg^-1 DM), lipid content (mg g^-1 DM) and essential amino acid composition (g per 16 gN) of cowpea seeds using 15 cultivars grown in three locations (Kano (12°00′ N 8°31′ E), Mokwa (9°17′ N 5°04′ E) and Ago-Iwoye (6°58′ N 4°00′ E)) that differ markedly in climate was studied. The environmental effect accounted largely for the variability observed in yield (93%), protein (71%), lipid (100%), threonine (96%), cystine (80%) and arginine (81%) while the genotypic effect accounted largely for the variability observed in methionine (56%) and lysine (51%) contents. Correlation coefficients (pooled data) from the three locations indicated that yield was negatively correlated to protein content (r=-0·87, P<0·001) and positively correlated to lipid content (r=0·73, P<0·001). Protein content was negatively correlated to lipid content (r=-0·67, P<0·001) and positively correlated to threonine (r=0·66, P<0·01), cystine (r=0·69, P<0·001) and methionine (r=0·88, P<0·001) contents. Similarly, yield was positively correlated to threonine (r=0·22, 0·01<P<0·05), cystine (r=0·38, 0·001<P<0·01) and methionine (r=0·67, 0·001<P<0·01). Yield showed a strong negative correlation with protein content (r=-0·81) and a strong positive correlation with lipid content (r=0·97) at the environmental level. Cystine, methionine and to some extent, threonine were the limiting amino acids in the three environments. This research established the degree of variability for these characters in cowpea and indicated that concurrent selection for yield, lipid content, threonine and sulphur amino acids compositions is feasible. © 1997 SCI.     

Instrumental Assessments of Japanese White Salted Noodle Quality

Strong correlations were found between some sensory evaluation results and instrumentally (Instron, Model 4301) assessed quality parameters for Japanese white salted noodles made from 32 Australian wheats. The sensory texture parameter, softness, had a strong negative correlation (r=-0·74, P<0·001) with the instrumental texture parameter, cutting force peak area divided by time. Other sensory texture parameters, smoothness and elasticity, showed significant correlations with another instrumental parameter, compression force peak area divided by time (r=-0·58, P<0·001 and r=0·52, P<0·01 respectively). Brightness, yellowness and discolouration of both raw and cooked noodles were measured using a colorimeter (Minolta, Model CR310). Strong correlations were observed between yellowness and discolouration of raw noodles and CIELAB b* (r=-0·79, P<0·001) and L*a* (r=-0·63, P<0·001) values, respectively. Similar relationships were found for cooked noodles (r=-0·74, P<0·001 for yellowness and r=-0·53, P<0·01 for discolouration). Both flour pasting properties including the flour swelling test and mixograph dough properties showed strong correlations with instrumental measures of noodle texture. Protein and ash content significantly affected noodle colour. In an attempt to simplify objective noodle quality measurements instrumental texture tests were carried out on flour gels. Textural measurements of flour gels showed that sensory softness of cooked noodles was correlated with an instrumental parameter, cutting peak force divided by time (r=-0·46, P<0·01). However, in this study no strong correlations were found between the smoothness and elasticity of noodles and any parameters of compression force-time profiles derived from gels. Yellowness of flour gels measured by a colorimeter showed a significant correlation with that of cooked noodles (r=-0·68, P<0·001). © 1997 SCI.     

Bestimmung natürlich vorkommender steroidaler Sexualhormone (Androgene und Gestagene) in Rindfleisch

The content of 10 naturally occurring steroidal sex hormones (androgens and progestogens), their biosynthetic precursors and metabolites was determined in 62 samples of beef (bulls, steers, heifers). After enzymatic hydrolysis of their conjugates, the steroids were extracted from the tissue by liquid-liquid extraction and purified by solid phase extraction. The identification and quantification was carried out by GC-MS of the trimethylsilyl ethers. The progestogens progesterone and pregnenolone were quantitatively dominant (43,7 and 6,5 μg/kg respectively). The highest steroid concentrations were determined in female cattle.     

Comparison of M. longissimus dorsi pigment concentration from implanted and control Angus and Limousin bulls and steers

M. longissimus dorsi total pigment concentration, visual color score and 24-h pH values were evaluated in a 2(3) factorial design that included bulls versus steers, Zeranol implants versus control and Angus versus Limousin comparisons. Bulls had greater total pigment concentration than steers (3.25 versus 2·90 mg/g; P < 0·01) and darker colored lean (P < 0·01). Twenty-four hour pH values did not differ between bulls and steers. Zeranol implanting and breed had no effect on total pigment concentration or visual color score; however, Limousin had higher (P < 0·05) 24-h pH values than Angus. The initial slaughter group (N = 10; average age = 256 days) had 34% less total pigment than the final slaughter group (N = 48; average age = 458 days). The correlation between visual color score and total pigment concentration was -0·65. These results indicate that the darker colored lean from bulls is due in part to an increase in pigment concentration.     

Influence of sonication on Warner-Bratzler shear force,colour and myoglobin of beef (<Emphasis Type="Italic">m. semimembranosus</Emphasis>)

Research in the past few decades has shown the potential benefits of using ultrasound treatment as a technique to enhance tenderness and sensory properties of meat and its sub-products. The objective of current study was to assess whether the low-frequency, low-intensity ultrasound treatment at 24 h postmortem affects the pH, Warner-Bratzler shear force (WBSF), colour (CIE L^*a^*b^*c^*H°), and relative proportions of myoglobin (Mb) redox forms and total Mb concentration during 96 h of beef (musculus semimembranosus) storage. Muscles were obtained from young bulls (n = 15) of Lowland Black and White breed slaughtered at a live weight of 475 (SD 16.1) kg. Ultrasound treatment did not have a statistically significant (p < 0.05) effect on the pH of meat directly after sonication (24 h postmortem), or at 72 and 96 h postmortem. Sonicated meat sample (S) was characterized by higher, but not statistically significant (p < 0.05), L* coordinate values 24, 48 and 72 h postmortem. During the whole storage period, colour coordinates a*b*c* and H° were not significantly (p < 0.05) affected by sonication. Ultrasound treatment accelerated the total colour change ΔE, limited the formation of MbO₂ and slowed down the formation of MetMb. Measurements carried out 48 and 72 h after slaughter revealed that the ultrasound treatment significantly (p < 0.05) reduced the WBSF. This study demonstrates the potential of low-frequency, low-intensity ultrasound treatment at 24 h postmortem for beef tenderization without detrimental effects on its CIE colour parameters and relative proportions of Mb redox forms.     

Addition of synthetic and natural antioxidants to α-tocopheryl acetate supplemented beef patties: effects of antioxidants and packaging on lipid oxidation

Friesian steers (n=5), aged 26–27 months, were fed a diet containing 2000 (supplemented) IU α-tocopheryl acetate/head/day for approximately 50 days prior to slaughter. Muscularis semimembranosus muscles from supplemented cattle were held in frozen storage (−20°C×12 weeks) following which they were minced and divided into five batches. The batches contained: (1) control, containing only vitamin E supplemented beef (C); (2) vitamin E supplemented beef with 4% soya oil (S); (3) vitamin E supplemented beef mixed with 0.2% Duralox NMC dissolved in 4% soya oil (R1); (4) vitamin E supplemented beef mixed with 0.25% Herbalox type 25 (containing 25 natural antioxidant extracts of rosemary) dissolved in 4% soya oil (R2); and (5) vitamin E supplemented beef mixed with a 1:1 mixture of 0.01% (w/w) BHA and 0.01% (w/w) BHT dissolved in 4% soya oil (B). The meat was then aerobically packaged (A) or packaged under the following modified atmospheres (MAP); 30:70 (M₁); 70:30 (M₂) or 80:20 (M₃) (O₂:CO₂). Oxidative stability (TBARS) and Hunter ‘a’ values (redness) were determined in all beef patties over 8 days of refrigerated (4°C) storage. Under MAP or aerobic packaging conditions, elevated oxygen levels brought about increased (P<0.05) TBARS numbers during refrigerated storage. However, the addition of rosemary extracts or BHA/BHT significantly (P<0.05) improved the oxidative stability of dietary α-tocopheryl acetate supplemented beef. Rosemary extracts were as effective in reducing TBARS as the combination of synthetic antioxidants, BHA/BHT.     

Growth and carcass fatty acid composition of beef steers fed soybean oil for increasing duration before slaughter

Duration of soybean oil (SBO) supplementation needed to enhance carcass conjugated linoleic acid (CLA) and trans-vaccenic (TVA) content was examined using 96 beef steers (293.6 ± 3.9 kg) fed a 78% corn-based diet supplemented with SBO for 0, 77, 137, or 189 days before slaughter. Duration of SBO supplementation had no effect (P ? 0.15) on animal performance or carcass traits, nor (P ? 0.15), total, total saturated, or total polyunsaturated fatty acids of Longissimus dorsi (LD). Concentrations of CLA in LD were not affected (P ? 0.18) by SBO supplementation. Concentrations of monounsaturated fatty acids (MUFA) decreased linearly (P = 0.03) in LD, whereas TVA increased (P = 0.04) in adipose tissue and tended (P = 0.07) to increase in LD with increasing duration of SBO supplementation. Supplementing SBO to a concentrate-based diet may enhance TVA without impacting CLA, while reducing the MUFA content of lean beef.