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Non-Invasive Methods to Predict Breast Muscle Weight in Slow-Growing Chickens  [PDF]
J.-M. Lariviere,C. Michaux,V. Verleyen,C. Hanzen
International Journal of Poultry Science , 2009,
Abstract: This experiment aims to compare in vivo breast morphometric and ultrasound measurements, as well as live body weight to predict breast meat weight in slow-growing chickens. Traits included Thoracic Circumference (TC), Chest Width (CW), Keel Length (KL) and angle (KA), Live Weight (LW), thickness of muscle determined by sonography (TM) and Breast Meat Weight (BMW). Birds were then slaughtered and total breast muscles (Pectoralis major and Pectoralis minor) were dissected and weighed. A linear model including sex effect and the different predictor measurements, as covariates, were adjusted to the data. Homogeneity test of slopes between sexes showed no difference. Means of the traits were 115.58g (±19.72) for BMW, 1031 g (±163.44) for LW, 68.65o (±6.89) for KA, 26.81 cm (±1.57) for TC, 10.40 cm (±0.62) for KL, 4.67 cm (±0.47) for CW and 11.52 mm ( ±1.11) for TM. All traits were highly correlated to BMW: TC (0.85), LW (0.84), KL (0.81) and TM (0.79), except for KA (0.28) and CW (0.19). Finally, TC, LW, KL and TM appear to be valuable indicators for estimating BMW in slow-growing chickens but KA and CW remain poor predictors.
Analysis of a slow-growing line reveals wide genetic variability of carcass and meat quality-related traits  [cached]
Chabault Marie,Baéza Elisabeth,Gigaud Vérane,Chartrin Pascal
BMC Genetics , 2012, DOI: 10.1186/1471-2156-13-90
Abstract: Background Slow-growing lines are widely used in France for the production of high quality free-range chickens. While such production is mainly dedicated to the whole carcass market, new prospects are opening up for the development of cuts and processed products. Whether the body composition and meat quality of slow-growing birds can be improved by selection has thus become an important issue. The genetic parameters of growth, body composition and breast meat quality traits were evaluated in relation to behaviour at slaughter in a large pedigree population including 1022 male and female slow-growing birds. Results The heritability coefficients (h2) of body weight and body composition traits varied from 0.3 to 0.5. Abdominal fat percentage was genetically positively correlated with body weight but negatively correlated with breast muscle yield. The characteristics of the breast meat (i.e., post-mortem fall in pH, colour, drip loss, shear-force and lipid content) were all heritable, with h2 estimates ranging from 0.18 to 0.48. The rate and extent of the fall in pH were under different genetic control. Strong negative genetic correlations were found between the ultimate pH and the lightness, yellowness and drip loss of the meat. Wing flapping on the shackle line was significantly heritable and exhibited marked genetic correlations with the pH at 15 min post-slaughter and the redness of the meat. The genetic relationships between meat quality traits, body weight and body composition appeared slightly different between males and females. Conclusion This study suggested that there are a number of important criteria for selection on carcass and breast meat quality in slow-growing birds. Selection for reduced abdominal fatness and increased breast muscle yield should be effective as both traits were found to be highly heritable and favourably correlated. Substantial improvement in meat quality could be achieved by selection on ultimate pH which was highly heritable and strongly correlated with the colour and water-holding capacity of the meat. Moreover, this study revealed for the first time that the behaviour at slaughter is partly genetically determined in the chicken.
The effect of genotype of broiler chickens on carcass quality in extensive rearing system
Blagojevi? M.,Pavlovski Zlatica,?krbi? Zdenka,Luki? M.
Acta Veterinaria , 2009, DOI: 10.2298/avb0901091b
Abstract: Research was carried out on chickens of four genotypes: two slow-growing genotypes, Master Gris (MG) and Farm Q (FQ), one fastgrowing, Hubbard Classic (HC) and one medium-growing Red Bro (RB). To the age of 3 weeks, chickens were reared according to all technological norms for intensive production. After that period, chickens were moved and fattening in extensive conditions resumed, using unlimited free range. The significance of genotype on body mass was established. The greatest final body mass was established in chickens of the Master Gris genotype (1983 g) and the lowest in Farm Q (1371 g). Fast-growing chickens of genotype Hubbard Classic at the age of 84 days had body mass at the level of medium-growing Red Bro genotype at the age of 91 days (1730 g, and 1759 g, respectively). In accordance to the established body mass, slaughter yields of Farm Q broilers were significantly the lowest. Also, chickens of this genotype also had significantly (p<0.05) lower share of abdominal fat compared to other genotypes. Chickens of Master Gris and Red Bro genotypes had significantly greater shank length (22.57 and 21.01 g/mm, respectively), whereas in fast-growing genotype Hubbard Classic a significantly greater breast angle (90.15 degrees) was determined. Accordingly, share of breast (15.90 %), as well as share of breast meat (10.11 %) was significantly greater in carcasses of Hubbard Classic chickens.
Genotype and Sex Effect on Gastrointestinal Nutrient Content, Microflora and Carcass Traits in Nigerian Native Chickens  [PDF]
Sunday O. Peters,Olusegun M.O. Idowu,Brilliant O. Agaviezor,Raphael O. Egbede
International Journal of Poultry Science , 2010,
Abstract: The nutrient concentration of crop and gizzard contents of three genotypes of indigenous scavenging chickens under rural conditions were investigated along-side with the micro-flora community of the Gastrointestinal Tract (GIT), body dimensions and carcass traits. Genotype significantly (p<0.01) affected the Crude Protein (CP) and Dry Matter (DM) values while Ether Extract (EE) value was significantly (p<0.05) influenced by sex of bird. The interaction between genotype and sex significantly (p<0.01) affected only CP and EE values while Crude Fibre (CF), ash and Gross Energy (GE) values were statistically similar across both genotype and sex of the bird. The genotype significantly (p<0.01) affected Live Weight (LWT), Bled Weight (BDWT), Plucked Weight (PLWT), Dressed Weight (DRWT), Breast Girth (BRG), liver weight, lung weight, heart weight, GIT weight and GIT length. The sex of bird also significantly (p<0.01) influenced Body Length (BLT), LWT, BDWT, PLWT, BRG, shank length, keel length, heart weight, gizzard weight, lung weight and GIT length while the interaction between genotype and sex significantly (p<0.05) affected LWT, BDWT, PLWT, DRWT, BRG, heart weight, gizzard weight and lung weight. Both genotype and sex significantly (p<0.01) influenced bacteria population of the chickens caeca. Salmonella sp., Escherichia coli and Staphylococcus aureus were prevalent in the caeca of all the scavenging birds. It was concluded that there are genotype and sex effects on crop and gizzard content, linear body measurements and presence or absence of bacteria in the caeca of the Nigerian native chickens raised under rural extensive system This findings further corroborates the abundance of genetic variation that can be exploited in developing any stock improvement programme for growth, carcass or disease resistance traits involving the Nigerian local chickens.
Fear Behaviour, Ease of Capture and Performance Traits of Growing Meat Type Chickens  [PDF]
K. Ghareeb,J. Bohm
International Journal of Poultry Science , 2008,
Abstract: The damaging effects of fear on a number of performance indicators in poultry and other farm animals are becoming increasingly recognized. Indeed, there is a growing evidence for the negative association between growth and fearfulness (an underlying behavioural characteristic). The present study examined the putative relationship between fearfulness and body weight in growing broiler chickens at age of harvesting (35-42 days old). As fearfulness is particularly influential trait in domesticated species, the finding that such trait respond to artificial selection may have important implications for poultry welfare and performance. However, it is not known how fearfulness and growth influenced human-animal interactions. The present experiment investigated also the influence of fearfulness and live body weight of broilers on the ease with which birds could be caught and handled. Furthermore, due to increasing the price of cereal grains in the last two years, it become necessary to evaluate the body weight gain and feed conversion efficiency at earlier age of growing period (5 wk) and comparing data from normal harvesting age in Europe (6 wk). The results showed a significant correlation between fearfulness and human animal interactions. Indeed, the duration of tonic immobility was higher for the birds captured first (rank 1) compared with birds captured afterwards (rank 2). This indicates that birds captured firstly were more fearful than birds afterwards. Moreover, the ease of capture rank was negatively correlated with the duration of tonic immobility at week 5 (-.364) and with the number of tonic immobility inductions at week 6 (-.238). This suggests that more fearful birds (birds had longer tonic immobility duration and higher number of tonic immobility inductions) were captured more easily than less fearful ones. Interestingly, body weight had a significantly negative correlation with the number of inductions required to induce tonic immobility reaction at week 6 (-.415, p < 0.05). This may indicate that heavier birds were less fearful (required less number of induction trials to induce tonic immobility) than lighter birds. Furthermore, the body weight gain was higher at week 5 (628±29g) than at week 6 (585±40g). The feed intake and feed conversion rate were lower at week 5 (985g and 1.57, respectively) than at week 6 (1075g and 1.84, respectively). This indicates that harvesting of growing broilers at week 5 is better for the broiler producers in the term of the economic costs especially after the elevation of prices of cereal grains during the last
Performance and behaviour of chickens with different growing rate reared according to the organic system
Cesare Castellini,Alessandro Dal Bosco,Cecilia Mugnai,Marcella Bernardini
Italian Journal of Animal Science , 2010, DOI: 10.4081/ijas.2002.291
Abstract: The performance and the behaviour of three different chicken strains, reared according to the EEC-Regulation 1804/1999 on organic system, were compared. The strains had very slow (Robusta maculata), slow (Kabir) and fast (Ross) growing rates, respectively. The trial was carried out on 200 chickens (male and female) per strain. Rearing lasted 81 days as required by the EEC Regulation. At slaughter age, 20 birds per group were killed. Robusta maculata and Kabir chickens showed more intense walking activity and better foraging aptitude; their antioxidant capacity was also superior. Ross chickens had a good growth rate and feed conversion index, reaching an excellent body weight, but the mortality and the culling rate were high indicating that fast-growing strains do not adapt well to organic production. Robusta macula- ta showed the worst productive performance although the mortality was low and Kabir birds gave intermediate results. The carcass traits were the best in Ross and the poorest in Robusta maculata. Male chickens were heavier and leaner than females.
Relationship between tissue retention efficiency and production traits in a slow-growing broiler population
JE Melo, JC Porteyro Ibarra, AI Erias, LR Morao, F Cortés Rondán, MC Miquel
South African Journal of Animal Science , 2007,
Abstract: An experiment was conducted using 96 individually caged male broilers between 49 and 77 d of age. One objective was to establish phenotypic relationships between some production traits [feed conversion ratio (FCR), feed consumption, residual feed consumption (RFC), relative weight gain (RWG), weight gain (WG) and live weight (LW)] and “tissue retention efficiency” (TRE) traits in a slow-growing broiler population. The other objective was the characterization of Campero-INTA broilers for TRE traits. Weight and feed consumption were recorded weekly. Forty four broilers were slaughtered at 44 d of age to estimate initial body composition while the remaining birds were slaughtered at 79 d of age. Ether extract and crude protein content of the carcasses were used to estimate TRE traits: Energy retained as protein (ERP), energy retained as fat (ERF), ERP/(ERP+ERF), ERF/(ERP+ERF), protein retention efficiency and lipid-protein ratio. Correlation coefficients between traits were obtained and regression analyses were done for the evaluation of the influence of production traits on TRE traits. The independent variable that best explained ERF was WG (R2 = 0.49). Inclusion of final LW and RWG raised the R2 to 0.58 and decreased the error term. The ERP was best explained by RWG (R2 = 0.37); lipid-protein ratio by final LW (R2 = 0.49); protein retention efficiency by FCR (R2 = 0.34) and fraction of retained energy (ERF-ERP/ERP+ERF) by WG (R2 = 0.29). The TRE traits were not well predicted by the measured production traits. The high phenotypic variability observed in some of the TRE traits suggested a need for further studies on these characteristics.
Identification of differentially expressed genes and pathways for intramuscular fat deposition in pectoralis major tissues of fast-and slow-growing chickens
Huanxian Cui, Ranran Liu, Guiping Zhao, Maiqing Zheng, Jilan Chen, Jie Wen
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-213
Abstract: Agilent cDNA microarray analyses were conducted to determine gene expression profiles of breast muscle sampled at different developmental stages of BJY and AA chickens. Relative to d 1 when there is no detectable IMF, breast muscle at d 21, d 42, d 90 and d 120 (only for BJY) contained 1310 differentially expressed genes (DEGs) in BJY and 1080 DEGs in AA. Of these, 34–70 DEGs related to lipid metabolism or muscle development processes were examined further in each breed based on Gene Ontology (GO) analysis. The expression of several DEGs was correlated, positively or negatively, with the changing patterns of lipid content or breast weight across the ages sampled, indicating that those genes may play key roles in these developmental processes. In addition, based on KEGG pathway analysis of DEGs in both BJY and AA chickens, it was found that in addition to pathways affecting lipid metabolism (pathways for MAPK & PPAR signaling), cell junction-related pathways (tight junction, ECM-receptor interaction, focal adhesion, regulation of actin cytoskeleton), which play a prominent role in maintaining the integrity of tissues, could contribute to the IMF deposition.The results of this study identified potential candidate genes associated with chicken IMF deposition and imply that IMF deposition in chicken breast muscle is regulated and mediated not only by genes and pathways related to lipid metabolism and muscle development, but also by others involved in cell junctions. These findings establish the groundwork and provide new clues for deciphering the molecular mechanisms underlying IMF deposition in poultry. Further studies at the translational and posttranslational level are now required to validate the genes and pathways identified here.
Comparison of the Genome-Wide DNA Methylation Profiles between Fast-Growing and Slow-Growing Broilers  [PDF]
Yongsheng Hu, Haiping Xu, Zhenhui Li, Xuejuan Zheng, Xinzheng Jia, Qinghua Nie, Xiquan Zhang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0056411
Abstract: Introduction Growth traits are important in poultry production, however, little is known for its regulatory mechanism at epigenetic level. Therefore, in this study, we aim to compare DNA methylation profiles between fast- and slow-growing broilers in order to identify candidate genes for chicken growth. Methylated DNA immunoprecipitation-sequencing (MeDIP-seq) was used to investigate the genome-wide DNA methylation pattern in high and low tails of Recessive White Rock (WRRh; WRRl) and that of Xinhua Chickens (XHh; XHl) at 7 weeks of age. The results showed that the average methylation density was the lowest in CGIs followed by promoters. Within the gene body, the methylation density of introns was higher than that of UTRs and exons. Moreover, different methylation levels were observed in different repeat types with the highest in LINE/CR1. Methylated CGIs were prominently distributed in the intergenic regions and were enriched in the size ranging 200–300 bp. In total 13,294 methylated genes were found in four samples, including 4,085 differentially methylated genes of WRRh Vs. WRRl, 5,599 of XHh Vs. XHl, 4,204 of WRRh Vs. XHh, as well as 7,301 of WRRl Vs. XHl. Moreover, 132 differentially methylated genes related to growth and metabolism were observed in both inner contrasts (WRRh Vs. WRRl and XHh Vs. XHl), whereas 129 differentially methylated genes related to growth and metabolism were found in both across-breed contrasts (WRRh Vs. XHh and WRRl Vs. XHl). Further analysis showed that overall 75 genes exhibited altered DNA methylation in all four contrasts, which included some well-known growth factors of IGF1R, FGF12, FGF14, FGF18, FGFR2, and FGFR3. In addition, we validate the MeDIP-seq results by bisulfite sequencing in some regions. Conclusions This study revealed the global DNA methylation pattern of chicken muscle, and identified candidate genes that potentially regulate muscle development at 7 weeks of age at methylation level.
Combining Abilities of Carcass Traits among Pure and Crossbred Meat Type Chickens
A.O. Adebambo,M.A. Adeleke,M. Whetto,S.O. Peters
International Journal of Poultry Science , 2010,
Abstract: Two hundred and ninety five cocks and two hundred and ninety nine hens were selected from a diallel combination of four breeds of chickens; [Anak Titan (A), Alpha (B), Giriraja (G) and Normal indigenous (N) chickens] at 12 weeks of age in a broiler improvement program for carcass analysis. The following data were collected in percentages: economically important traits = Live weight (g), Plucked weight, Eviscerated weight, Carcass yield, Abdominal fat percentage, Breast yield, Thigh yield, Drumstick yield; survival organs = Wing yield, Internal organ, Empty gizzard yield, Heart yield, Lung yield, Kidney yield, Liver yield. Analyses of variance of carcass traits show that sire and dam genotype significantly (p<0.05) affected carcass traits. Anak Titan sires and dams performed best in economically important traits, while N and B performed better in survival organs. Sex had significant (p<0.05) effect only on live weight with cocks having higher values of 979.55±56.62 and hens 879.6±34.18. Results of diallel analysis to test for general and specific combining abilities of breeds on traits showed that additive genetic effects were important in determining economically important traits, indicative that improvement can be achieved by selection. Dominance effects were important in control of survival organs, indicative of improvement by crossbreeding. Estimates of GCA for carcass traits show that Anak Titan had highest general combining ability for most of the carcass parameters while the least values were found among Alpha chickens. Estimates of SCA for carcass parameters showed AN cross generally had highest SCA for most of the carcass traits. Least SCA values for carcass parameters were generally recorded for AB crosses. It is recommended that an improvement process that involves all the breeds should be adapted using reciprocal recurrent selection or modifications of it.
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