F. Sirri

Histology, composition, and quality traits of chicken Pectoralis major muscle affected by wooden breast abnormality

Only a few years ago, the poultry industry began to face a recent abnormality in breast meat, known as wooden breast, which frequently overlaps with white striping. This study aimed to assess the impact of wooden breast abnormality on quality traits of meat. For this purpose, 32 normal (NRM), 32 wooden (WB), and 32 wooden and white-striped (WB/WS) Pectoralis major muscles were selected from the same flock of heavy broilers (males, Ross 708, weighing around 3.7 kg) in the deboning area of a commercial processing plant at 3 h postmortem and used to assess histology, proximate (moisture, protein, fat, ash, and collagen) and mineral composition (Mg, K, P, Na and Ca), sarcoplasmic and myofibrillar protein patterns, and technological traits of breast meat. Compared to the normal group, WB/WS fillets showed more severe histological lesions characterized by fiber degeneration, fibrosis, and lipidosis, coupled with a significantly harder texture. With regard to proximate and mineral composition, abnormal samples exhibited significantly (P < 0.001) higher moisture, fat, and collagen contents coupled with lower (P < 0.001) amounts of protein and ash. Furthermore, increased calcium (131 vs. 84 mg kg(-1); P < 0.05) and sodium (741 vs. 393 mg kg(-1); P < 0.001) levels were found in WB/WS meat samples. The SDS-PAGE analysis revealed a significantly lower amount of calcium-ATPase (SERCA, 114 kDa), responsible for the translocation of Ca ions across the membrane, in normal breasts compared to abnormal ones. As for meat quality traits, fillets affected by wooden abnormality exhibited significantly (P < 0.001) higher ultimate pH and lower water-holding/water-binding capacity. In particular, compared to normal, abnormal samples showed reduced marinade uptake coupled with increased drip loss and cooking losses as well. In conclusion, this study revealed that meat affected by wooden breast or both wooden breast and white striping abnormalities exhibit poorer nutritional value, harder texture, and impaired water-holding capacity.

Fatty acid composition of chicken breast meat is dependent on genotype-related variation of FADS1 and FADS2 gene expression and desaturating activity

In Western countries the dietary guidance emphasizes the need to decrease the intake of saturated fatty acids and to replace them with polyunsaturated fatty acids (PUFA), particularly long chain n-3 PUFA (LC-PUFA). The production of poultry meat having a lower fat content and healthier fatty acid (FA) profile is a hot topic for the poultry industry, and the possibility to identify genotypes able to produce meat with a higher LC-PUFA content deserves attention. The aims of the present study were to evidence in chicken (i) a genotype-related different expression of the desaturating enzymes delta-6 (Δ6, EC 1.14.99.25), delta-5 (Δ5, EC 1.14.19.) and delta-9 (Δ9, EC 1.14.19.1); (ii) the impact of the hypothesized different expression on the meat FA composition; (iii) the distribution of desaturase products in the different lipid classes. Slow (SG), medium (MG) and fast (FG) growing chickens fed the same diet were evaluated either for the relative expression of FADS1, FADS2 and SCD1 genes in liver (by q-PCR), or for the FA composition of breast meat. MG and particularly SG birds showed a greater expression of FADS2 and FADS1 genes, a higher Δ6 and Δ5 activity (estimated using desaturase indices), and consequently a higher LC-PUFA content in the breast meat than FG birds. The relationship between genotype and desaturating ability was demonstrated, with a significant impact on the PUFA content of breast meat. Due to the high consumption rate of avian meat, the identification of the best genotypes for meat production could represent an important goal not only for the food industry, but also for the improvement of human nutrition.

Effect of different levels of dietary zinc, manganese, and copper from organic or inorganic sources on performance, bacterial chondronecrosis, intramuscular collagen characteristics, and occurrence of meat quality defects of broiler chickens

The aim of the experiment was to assess the effects of 2 dietary levels of trace minerals (TM) zinc, manganese, and copper either from organic (OTM) or inorganic (ITM) sources on broiler performance, carcass traits, intramuscular collagen (IMC) properties, occurrence of hock burns (HB), foot pad dermatitis (FPD), femoral and tibia head necrosis, and breast muscle abnormalities (white striping, WS; wooden breast, WB; poor cohesion, PC). A total of 3,600 one-day-old male chicks were randomly assigned to one of 4 dietary treatments in a 2 × 2 factorial arrangement (9 replicates of 100 birds/dietary treatment). Birds were slaughtered at 31 (thinning) and 51xa0d of age. Body weight, daily weight gain (DWG), feed intake, feed conversion rate (FCR), and mortality were determined. A significant effect of the source of TM supplementation was found only in 51-day-old chickens. Birds of the OTM groups were heavier (P < 0.05), with a higher (P < 0.05) DWG and a better FCR (P < 0.05) compared with those of the ITM groups. OTM significantly reduced the lesion scores of femoral head (P = 0.004) and total leg (femur + tibia, P = 0.02) compared to ITM, which is mainly caused by the reduction of the percentages of femoral head transitional degeneration (FHT, P = 0.04) and femoral head necrosis (FHN, P = 0.07). Carcass traits were similar among the experimental groups. No alleviating effect of TM administration on the incidence of FPD and HB in 31- and 51-day-old chickens was found. Similarly, the occurrence and the degrees of WS and WB in 51-day-old chickens was affected neither by the doses nor by the source of TM supplied. IMC characteristics of broiler pectoral muscle were not affected (P > 0.05) by the different sources and doses of TM administrated.

Implications of white striping and spaghetti meat abnormalities on meat quality and histological features in broilers

During the past few years, there has been an increasing prevalence of broiler breast muscle abnormalities, such as white striping (WS) and wooden breast conditions. More recently, a new muscular abnormality termed as spaghetti meat (SM) because of the altered structural integrity of the Pectoralis major muscle often associated with WS has emerged. Thus, this study aimed at evaluating the effects of WS and SM conditions, occurring alone or combined within the same P. major muscle, on meat quality traits and muscle histology. In two replications, 96 P. major muscles were classified into four classes: normal (N), WS, SM and WS/SM. The whole fillet was used for weight assessment and morphometric measurements, then each sample was cut in order to separate the superficial layer from the deep one and used to evaluate proximate composition, histological features, nuclear magnetic resonance relaxation times, functional properties and both myofibrillar and sarcoplasmic proteins profile. Fillets affected by WS and SM abnormalities exhibited higher weights and increased thickness and length. SM condition was associated with a relevant decrease in protein content coupled with a significant increase in moisture level, whereas fat content was affected only by the simultaneous presence of WS. Histological evaluations revealed that abnormal samples were characterized by several degenerative aspects that almost completely concerned the superficial layer of the fillets. White striped fillets exhibited necrosis and lysis of fibers, fibrosis, lipidosis, loss of cross striation and vacuolar degeneration. Moreover, SM samples were characterized by poor fiber uniformity and a progressive rarefaction of the endo- and peri-mysial connective tissue, whereas WS/SM fillets showed intermediate histological features. Nuclear magnetic resonance relaxation analysis revealed a higher proportion of extra-myofibrillar water in the superficial section of all the abnormal fillets, especially in SM samples, which consequently led to a reduction of the water holding capacity of meat. As for functional properties, abnormal fillets exhibited a lower protein solubility and higher ultimate pH values on both the superficial and deep sections. Although abnormal fillets exhibited higher yellowness values, no relevant effect on meat color was observed. The occurrence of WS and SM abnormalities led to increased carbonylation levels and more intense proteolytic processes. Overall, muscle abnormalities mainly affect the superficial layer of P. major muscle and particularly the occurrence of SM myopathy seems to implicate a more pronounced modification of meat quality traits than the mere presence of WS.

Effect of dietary supplementation of lysophospholipids on productive performance, nutrient digestibility and carcass quality traits of broiler chickens

Abstract An experiment was carried out to evaluate productive performance, nutrient digestibility and carcass quality traits of broiler chickens fed diets supplemented with an exogenous emulsifier based on lysophospholipids prepared by enzymatic conversion of soy lecithin. One thousand seven-hundred and fifty-five one-day-old male Ross 308 chicks were randomly divided into three experimental groups of nine replications each: control group (CON) fed a corn–soybean basal diet, and two groups fed CON diet supplemented with constant (1u2009kg/ton) or variable (1–1.5u2009kg/ton) level of emulsifier (CONST and VARI, respectively). At the end of the trial (42 d), birds receiving the emulsifier had a statistically significant (pu2009<u20090.05) lower feed conversion rate compared to the control. Body weight and daily weight gain were only slightly influenced by lysophospholipids supplementation, while mortality and feed intake resulted similar among the groups. No statistically significant effect of the emulsifier was observed on nutrient digestibility as well as slaughtering yields, skin pigmentation and incidence of foot pad dermatitis. The results obtained in this study suggest that the use of an emulsifier based on lysophospholipids improves feed efficiency while showed limited effect on carcass quality traits.

Distribution of α-transducin and α-gustducin immunoreactive cells in the chicken (Gallus domesticus) gastrointestinal tract

The expression and distribution patterns of the taste signaling molecules, α-gustducin (Gαgust) and α-transducin (Gαtran) G-protein subunits, were studied in the gastrointestinal tract of the chicken (Gallus domesticus) using the immunohistochemical method. Gαgust and Gαtran immunoreactive (-IR) cells were observed in the mucosal layer of all examined segments, except the esophagus, crop, and the saccus cranialis of the gizzard. The highest numbers of Gαgust and Gαtran-IR cells were found in the proventriculus glands and along the villi of the pyloric, duodenum, and rectal mucosa. Gαgust and Gαtran-IR cells located in the villi of the jejunum, ileum, and cloaca were much less numerous, while only a few Gαgust and Gαtran-IR cells were detected in the mucosa of the proventriculus and cecum. In the crypts, IR cells were observed in the small and large intestine as well as in the cloaca. Gαgust and Gαtran-IR cells displayed elongated (bottle- or pear-like) or rounded shape. The demonstration of Gαgust and Gαtran expression provides evidence for taste receptor mediated mucosal chemosensitivity in the chicken gastrointestinal tract.

Effect of dietary supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) on caecum microbioma and productive performance in broiler chickens

This study examines the effects of the dietary supplementation with Lactobacillus acidophilus D2/CSL (CECT 4529) (LA) on productive performances, incidence of foot pad dermatitis and caecum microbioma in broiler chickens. A total of 1,100 one-day old male Ross 308 chicks were divided into 2 groups of 16 replicates with 25 birds each and reared from 1–41 d. One group was fed a basal diet (CON) and the other group the same diet supplemented with LA. Caecum contents were collected from 4 selected birds at day one and 5 selected birds at the end of the rearing period. Then, they were submitted to DNA extraction and whole DNA shotgun metagenomic sequencing. Overall, the LA supplementation produced a significant beneficial effect on body weight gain between 15–28 d and improved feed conversion rate in the overall period. On the contrary, litter moisture, pH and incidence of the foot pad lesions were not affected by LA. Birds treated with LA showed a lower occurrence of pasty vent at both 14 and 28 d. At the end of the rearing period, Lachanospiraceae were significantly higher in LA birds in comparison to CON (17.07 vs 14.39%; P = 0.036). Moreover, Ruminococcus obeum, Clostridium clostridioforme, Roseburia intestinalis, Lachnospiraceae bacterium 14-2T and Coprococcus eutactus were significantly higher in LA birds in comparison to CON. The relative abundance of Lactobacillus acidophilus was comparable between LA and CON groups. However, a positive effect was observed in relation to the metabolic functions in the treated group, with particular reference to the higher abundance of β-glucosidase. In conclusion, the LA supplementation improved broiler productive performances and metabolic functions promoting animal health.

Variability and interaction of some egg physical and eggshell quality attributes during the entire laying hen cycle

&NA; The aim of this study was to investigate the variability and relationships between some egg physical (egg weight, width, length, shape index, and surface area) and eggshell parameters (weight and percentage, thickness, breaking strength, and L*, a*, and b* values) during the entire laying hen cycle. A total of 8,000 eggs was collected every 5 wk, from 30 to 81 wk of hen age (10 samplings of 400 eggs/house), in 2 identical poultry houses equipped with enriched cages. For the statistical analysis, ANOVA, Bivariate Correlation, Principal Component Analysis (PCA), and Hierarchical Cluster Analysis were used. An increase of egg weight, length, and eggshell lightness (L*) associated with a reduction of eggshell percentage, breaking strength, and redness (a*) was observed as the hen aged (P < 0.05). Overall, the coefficients of variation resulted in <5% in width, length, shape index, and egg surface area; from 5 to 10% of egg weight, shell weight, shell percentage, shell thickness, L*, and b*; and >10% of eggshell breaking strength and a*. According to the PCA, the highest changes during the laying cycle are related to egg physical parameters (32%) and to eggshell breaking strength, percentage, and thickness (26%). The egg physical parameters appeared to be strongly correlated to each other, whereas a slight correlation between eggshell breaking strength and color attributes were evidenced (‐0.231 and 0.289, respectively, for L* and a*; P < 0.01). Hierarchical cluster analysis, based on principal components of the overall egg attributes, is hereby considered, and evidenced dissimilarities for eggs laid from peak production up for 39 wk of hen age from the eggs laid afterwards. The latter group could also be divided into 2 subgroups, one comprising eggs laid from 44 and 53 wk of hen age and the other from 58 wk to the end. In conclusion, the large dataset created in this study allowed to extrapolate some robust information regarding the variability and correlations of the egg physical and eggshell quality attributes throughout the entire laying hen cycle.

Enteroendocrine profile of α-transducin and α-gustducin immunoreactive cells in the chicken (Gallus domesticus) gastrointestinal tract

The enteroendocrine profile and distribution patterns of the taste signaling molecules, α-gustducin (Gαgust) and α-transducin (Gαtran) protein subunits, were studied in the gastrointestinal (GI) tract of the chicken (Gallus domesticus) using double labeling immunohistochemistry. Gαtran or Gαgust immunoreactivity was observed in enteroendocrine cells (EEC) expressing different peptides throughout the entire GI tract with different density. In the proventriculus tubular gland, Gαtran or Gαgust/gastrin (GAS) immunoreactive (-IR) cells were more abundant than Gαtran/or Gαgust containing glucagon-like peptide-1 (GLP-1) or peptide YY (PYY), whereas only few Gαtran or Gαgust cells co-stored ghrelin (GHR) or 5-hydroxytryptamine (5-HT). In the pyloric mucosa, many Gαtran or Gαgust-IR cells co-expressed GAS or GHR, with less Gαtran or Gαgust cells containing GLP-1, PYY, or 5-HT. In the small intestine, a considerable subset of Gαtran or Gαgust-IR cells co-expressed 5-HT in the villi of the duodenum and ileum, PYY in the villi of the jejunum, CCK or GLP-1 in the villi of the ileum, and GHR in the duodenum crypts. In the large intestine, many Gαtran or Gαgust-IR cells contained 5-HT or GLP-1 in the villi of the rectum, whereas some Gαtran/Gαgust-IR cells co-expressed PYY- or CCK-, and few Gαtran/Gαgust-IR cells were positive for GHR-IR. In the cecum, several Gαtran or Gαgust-IR cells were IR for 5-HT. Finally, many Gαtran/Gαgust cells containing 5-HT were observed in the villi and crypts of the cloaca, whereas there were few Gαtran or Gαgust/CCK-IR cells. The demonstration that Gα-subunits are expressed in the chicken GI enteroendocrine system supports the involvement of taste signaling machinery in the chicken chemosensing processes.