Thymus and meat physicochemical measurements to discriminate calves treated with anabolic and therapeutic doses of dexamethasone.

To preserve the Europe consumers' health, the use of glucocorticoids as growth promoters is prohibited in cattle fattening. In 2008, the Italian Ministry of Health associated to the official control a national monitoring plan based on the histological thymus analysis to identify animals illegally treated with corticosteroids. However, since corticosteroids are authorized and widely used for therapeutic purposes, it is necessary to verify whether the thymus histological test and some physicochemical traits in meat are able to discriminate doped calves from dexamethasone therapeutic treated ones. The aims of this study were (i) to establish whether the therapeutic and illicit corticosteroid treatments of calves could be differentiated through histological evaluation of thymus and by physicochemical meat traits; (ii) to identify a restricted number of physicochemical traits that could differentiate dexamethasone treated from untreated calves. Three groups of 15 calves each were included in this study: group dexamethasone therapeutic treatment treated with dexamethasone 21-phosphate disodium salt at a therapeutic dose (2 mg/kg of live weight for three consecutive days); group dexamethasone anabolic treatment orally treated with dexamethasone 21-phosphate disodium salt according to a presumed anabolic protocol (0.4 mg/day per animal for 20 days); group placebo control treated with a placebo served as control. Results demonstrated that groups could be easily discriminated by thymus microscopy as well as by two meat markers, namely, cooking loss and shear firmness or Warner-Bratzler shear force. The combination of thymus microscopic features and meat physicochemical traits could be used as a practical, economic and accurate screening strategy to discriminate between meat from illegally and therapeutically treated calves. This new reliable and simple tool could contribute to identify animals treated with dexamethasone in those countries where glucocorticoids are illegally used as growth promoters. More in general, this system could be included in the framework of official controls, and applied to verify suppliers' reliability by the meat industry.

Genome-wide association and pathway analysis of carcass and meat quality traits in Piemontese young bulls.

A key concern in beef production is how to improve carcass and meat quality traits. Identifying the genomic regions and biological pathways that contribute to explaining variability in these traits is of great importance for selection purposes. In this study, genome wide-association (GWAS) and pathway-based analyses of carcass traits (age at slaughter (AS), carcass weight (CW), carcass daily gain (CDG), conformation score and rib-eye muscle area) and meat quality traits (pH, Warner-Bratzler shear force, purge loss, cooking loss and colour parameters (lightness, redness, yellowness, chroma, hue)) were conducted using genotype data from the 'GeneSeek Genomic Profiler Bovine LD' array in a cohort of 1166 double-muscled Piemontese beef cattle. The genome wide-association analysis was based on the GRAMMAR-GC approach and identified 37 significant single nucleotide polymorphisms (SNPs), which were associated with 12 traits (P<5 × 10-5). In particular, 14 SNPs associated with CW, CDG and AS were located at 38.57 to 38.94 Mb on Bos taurus autosome 6 and mapped within four genes, that is, Leucine Aminopeptidase 3, Family with Sequence Similarity 184 Member B, Non-SMC Condensin I Complex Subunit G and Ligand-Dependent Nuclear Receptor Corepressor-Like. Strong pairwise linkage disequilibrium was found in this region. For meat quality traits, most associations were 1 SNP per trait, except for a signal on BTA25 (at ~11.96 Mb), which was significant for four of the five meat colour parameters assessed. Gene-set enrichment analyses yielded significant results for six traits (right-sided hypergeometric test, false discovery rate <0.05). In particular, several pathways related to transmembrane transport (i.e., oxygen, calcium, ion and cation) were overrepresented for meat colour parameters. The results obtained provide useful information for genomic selection for beef production and quality in the Piemontese breed.

Evaluation of the suitability of a partially defatted black soldier fly (Hermetia illucens L.) larvae meal as ingredient for rainbow trout (Oncorhynchus mykiss Walbaum) diets.

BACKGROUND: Two trials were performed to evaluate a partially defatted Hermetia illucens (HI) larvae meal as potential feed ingredient in rainbow trout (Oncorhynchus mykiss Walbaum) diets. In the first trial, 360 trout (178.9 ± 9.8 g of mean initial body weight) were randomly divided into three experimental groups (4 tanks/treatment, 30 fish/tank). The fish were fed for 78 days with isonitrogenous, isolipidic and isoenergetic diets containing increasing levels of HI, on as fed basis: 0% (HI0, control diet), 25% (HI25) and 50% (HI50) of fish meal substitution, corresponding to dietary inclusion levels of 0, 20% and 40%. In the second trial, 36 trout (4 tanks/treatment, 3 fish/tank) were used to evaluate the in vivo apparent digestibility coefficients (ADC) of the same diets used in the first trial. RESULTS: Survival, growth performance, condition factor, somatic indexes, and dorsal fillet physical quality parameters were not affected by diet. The highest dietary inclusion of HI larvae meal increased dry matter and ether extract contents of trout dorsal fillet. The use of HI larvae meal induced a decrease of valuable polyunsaturated fatty acids (PUFA) even if differences were only reported at the highest level of HI inclusion. The insect meal worsened the lipids health indexes of the same muscle. Dietary inclusion of insect meal did not alter the villus height of the fish. No differences were found among treatments in relation to ADC of ether extract and gross energy, while ADC of dry matter and crude protein were higher in HI25 if compared to HI50. CONCLUSIONS: The obtained results showed that a partially defatted HI larvae meal can be used as feed ingredient in trout diets up to 40% of inclusion level without impacting survival, growth performance, condition factor, somatic indexes, dorsal fillet physical quality parameters, and intestinal morphology of the fish. However, further investigations on specific feeding strategies and diet formulations are needed to limit the observed negative effects of the insect meal on the FA composition of dorsal muscle.

Dried artichoke bracts in rabbits nutrition: effects on the carcass characteristics, meat quality and fatty-acid composition.

In this study, the effects of the inclusion of artichoke bracts (AB) in rabbit diets on the carcass characteristics and rabbit meat quality were studied. A total of 120 rabbits aged 38 days were used and divided into three groups that were fed with different isonitrogenous and isocaloric diets supplemented with AB at 0%, 5% and 10%. The animals were single housed in wire cages at a temperature of 22±2°C and had free access to clean drinking water. At 96 days of age, 12 rabbits/group were slaughtered in an experimental slaughterhouse without fasting. The carcass was weighed and the weights of the skin and full gastrointestinal tract were recorded. Carcasses were chilled at +4°C for 24 h in a refrigerated room. The chilled carcass weight (CCW), dressing out percentage (CCW as percentage of slaughter weight), and the ratio of the head and liver were determined as a percentage of CCW. The reference carcass weight was also calculated. Carcasses were halved and the two longissimus dorsi (LD) muscles were excised. The left LD muscle was divided into two parts. The fore part was used to measure pH, colour and cooking losses. The hind part of the left LD was vacuum-packed, frozen at -20°C and then freeze-dried. Proximate composition, fatty-acid profile and thiobarbituric acid-reactive substances values were determined on freeze-dried samples. Results showed that carcass characteristics, LD muscle traits and its oxidative status were not affected by the AB supplementation, except for the meat ether extract content that increased from 0.68% to 0.94% on fresh matter basis with the increase of the AB supplementation (P<0.01). The α-linolenic acid proportion decreased with the increase of the AB supplementation from 3.58% to 2.59% in the LD muscle and from 4.74% to 3.62% in the perirenal fat, whereas the n-6/n-3 ratio increased significantly with increasing AB inclusion from 7.15 to 10.20 in the LD muscle and from 6.68 to 9.35 in the perirenal fat (P<0.01). Furthermore, no significant difference was found in preference among meat samples from each group. The enrichment of the rabbit's diet with AB allows the production of rabbit meat with a good degree of unsaturation and low saturation, even if the n-6/n-3 ratio was slightly worse.

Fatty acid profile and cholesterol content of beef at retail of Piemontese, Limousin and Friesian breeds.

Samples of longissimus thoracis muscle of young bulls belonging to Piemontese (n=10), Limousin (n=11) and Friesian (n=10) breeds were analysed in order to study the chemical composition, fatty acids and cholesterol content of beef purchased at retail. The breeds and their differences in intramuscular fat content strongly influenced the fatty acids profile. The Piemontese animals displayed the lowest intramuscular fat and SFA content, while Friesian animals showed the highest intramuscular fat, SFA and MUFA content. In general, Limousin animals had intermediate characteristics. A higher PUFA proportion on total fatty acids was observed in Piemontese breed, but the PUFA absolute content (mg/100 g meat) did not differ among breeds. All the three breeds displayed a high content of n-6 fatty acids family and, consequently, a very unbalanced n-6/n-3 ratio. No differences were found for cholesterol content.

Effects of tomato pomace supplementation on carcass characteristics and meat quality of fattening rabbits.

The aim of this study was to determine how a feeding plan characterized by different levels of tomato pomace (TP) supplementation influences the carcass characteristics, the chemical, physical and sensorial characteristics of rabbit meat. 144 weaned crossbred rabbits were divided into three groups of 48 each. The first group was fed a basal diet without TP, while the other two groups were fed the basal diet after replacing part of the diet with TP at 3% and 6%, respectively. There was a significant difference between the experimental groups in terms of live and carcass weights. The meat of rabbits fed on a 6% TP diet exhibited higher yellowness (b*) and Chroma values when compared to others. The saturated fatty acid content in the longissimus dorsi muscle and perirenal fat decreased significantly with increasing TP inclusion, while polyunsaturated fatty acids increased. Furthermore, our results indicate that a diet integrated with 6% TP could influence positively the overall preference of cooked meat.

Lipomatous muscular 'dystrophy' of Piedmontese cattle.

Lipomatous myopathy is a degenerative muscle pathology characterized by the substitution of muscle cells with adipose tissue, sporadically reported in cattle, pigs, and rarely in sheep, horses and dogs. This study investigated the pathology of this myopathy in 40 muscle samples collected from regularly slaughtered Piedmontese cattle living in Piedmont region (Italy). None of the animals showed clinical signs of muscular disease. Muscle specimens were submitted to histological and enzymatic investigations. Gross pathology revealed a different grade of infiltration of adipose tissue, involving multiple or single muscles. The most affected regions were the ventral abdomen and the shoulders, especially the cutaneous muscles and the muscles of the thoracic group. Morphological staining revealed an infiltration of adipose tissue varying in distribution and severity, changes in muscle fibre size and increased number of fibres with centrally located nuclei, suggesting muscle degeneration-regeneration. Necrosis and non-suppurative inflammatory cells were also seen. Furthermore, proliferation of connective tissue and non-specific myopathic changes were present. Chemical and physical characteristics of the affected tissue were also evaluated. The authors discuss about the aetiopathogenesis and classification of this muscle disorder whose histological lesions were similar to those reported in human dystrophies.

Relationship between beef consumer tenderness perception and Warner-Bratzler shear force.

The aim of this study was to determine consumer ability to discern different levels of beef tenderness established by Warner-Bratzler shear (WBs). A panel of 220 people evaluated 60 samples of longissimus thoracis using a 5-point intensity scale (1: very tough; 5: very tender). Samples differed for commercial category, breed of animals and ageing length of meat. Shear force was measured by Instron equipped with a Warner-Bratzler device on 1.27cm diameter cores. Correlation coefficient of WBs measurements with tenderness sensory ratings was -0.72. WBs value corresponding to class 3 of the sensory tenderness was 47.77N. From this value, the range of WBs (22.96-72.59N) was split into five categories to which connect the five classes of sensory tenderness. The results suggest consumers' difficulty in discriminating category 1 (WBs>62.59N) from category 2 (WBs: 52.78-62.59N) and a greater inclination to distinguish category 5 (WBs<32.96N). As WBs category boundaries were probably too restrictive for the panel's selective ability, WBs scale was reduced to 3 categories by joining the two extreme categories (i.e. category 2 with 1 and category 4 with 5). In this case, 55.6% of consumers significantly discriminated tough from intermediate and tender meat and 62.3% distinguished tender from intermediate and tough meat (P<0.01). Hence, WBs values >52.68N and <42.87N allow classification of tough and tender beef in a sufficiently reliable way.

Polymorphism of the GHR gene in cattle and relationships with meat production and quality.

Growth hormone (GH) exerts its effects on growth and metabolism by interacting with a specific receptor (GHR) on the surface of the target cells. Therefore, GHR has been suggested as candidate gene for traits related to meat production in cattle. The aim of the study was to analyse the polymorphism at position 257 in exon 10 of the GHR gene and investigate relationships with 14 in vivo traits and four meat characteristics in Piemontese animals. The biallelic polymorphism already described was detected using a new PCR procedure. The statistical analysis did not show significant gene substitution effects on growth, size and meat conformation traits. As for meat characteristics, a significant gene substitution of GHR(A) over GHR(G) was observed for drip losses at day 3, with the allele GHR(A) associated with higher values. A significant dominance effect was also observed for this trait. Further investigations in other breeds will be useful for better understanding information on the effect of this GHR polymorphism.

Effect of castration on meat quality in Piemontese cattle.

The effect of early (5 month) or late castration (13 month) on meat quality of hypertrophied Piemontese cattle was investigated. Twenty four animals, equally divided into three groups (early castrated, EC; late castrated, LC; intact males, IM) were reared under the same experimental conditions and slaughtered at the same age. Twenty four hours after slaughter the pH was measured on the longissimus thoracis of the right side. After 11 days of ageing the following analyses were performed on the longissimus thoracis et lumborum: water, protein and ether extract contents, hydroxyproline content and collagen solubility, colour (L, a(L), b(L), hue and chroma), drip and cooking losses, Warner-Bratzler shear values and sensory analysis (appearance of the raw meat and eating qualities of the cooked meat). Compared with intact males, the castrates had lower water and hydroxyproline contents and higher contents of protein and ether extract. No significant differences were observed between early and late castration, except for cooking losses.

The use of principal component analysis (PCA) to characterize beef.

Principal component analysis was performed to study the relationships between chemical, physical and sensory variables (n=18) measured on longissimus thoracis et lumborum of 79 young bulls from the following ethnic groups: hypertrophied Piemontese, normal Piemontese, Friesian, crossbred hypertrophied Piemontese×Friesian, Belgian Blue and White. The first three PCs explained about 63% of total variability. Sensory characteristics, protein content, shear force and cooking losses resulted the most effective variables for the PC1, while hydroxyproline and ether extract content, as well as hue and lightness were useful to define the PC2. The distribution of the objects on the axes of the first two PCs allowed the identification of two groups, the first one including meats of the hypertrophied animals (Piemontese and Belgian Blue and White) the second one including normal Piemontese and Friesian. However, a considerable variability within groups was noted. The crossbreds were placed between the two previous groups. In conclusion, PCA proved to be a very effective procedure to obtain a synthetic judgement of meat quality.

Two reading techniques of the filter paper press method for measuring meat water-holding capacity.

Two systems of measuring the areas obtained from the filter paper press method (Grau & Hamm) on meat (beef) were compared: by planimeter (method A) and by optical-electronic system (Video Image Analyzer; method B). Data obtained by three operators, measuring 15 samples twice, were utilized to estimate the 'precision' of the two methods. The general mean area of ring zone resulting from method A was 6·69 cm(2). Analysis of variance demonstrated a significant influence both for 'operator' factor and for the interaction operator-sample. Repeatability and reproducibility were 0·1706 and 0·2580, respectively. By method B the general mean area was 6·67 cm(2). The variance among operators was significant, but lower than in the method A, and there was no interaction. The repeatability and reproducibility were 0·03055 and 0·07234, respectively. It would appear, therefore, that the optical-electronic determination is more precise than the planimetric method.