Biomedical subjects

A L J Vereijken

Publications and source records attributed to A L J Vereijken.

8 recordsLinked to original sources

PubMed2005

Genetic parameters of ascites-related traits in broilers: correlations with feed efficiency and carcase traits.

(1) Pulmonary hypertension syndrome followed by ascites is a metabolic disorder in broilers that occurs more often in fast-growing birds and at cool temperatures. (2) Knowledge of the genetic relationships among ascites-related traits and performance traits like carcase traits or feed efficiency traits is required to design breeding programmes that aim to improve the degree of resistance to ascites syndrome as well as production traits. The objective of this study was to estimate these genetic correlations. (3) Three different experiments were set up to measure ascites-related traits (4202 birds), feed efficiency traits (2166 birds) and carcase traits (2036 birds). The birds in different experiments originated from the same group of parents, which enabled the estimation of genetic correlations among different traits. (4) The genetic correlation of body weight (BW) measured under normal conditions and in the carcase experiment with the ascites indicator trait of right ventricle to total ventricle ratio (RV:TV) measured under cold conditions was 0.30. The estimated genetic correlation indicated that single-trait selecting for BW leads to an increase in occurrence of the ascites syndrome but that there are realistic opportunities of multi-trait selection of birds for improved BW and resistance to ascites. (5) Weak but positive genetic relationships were found between feed efficiency and ascites-related traits suggesting that more efficient birds tend to be slightly more susceptible to ascites. (6) The relatively low genetic correlation between BW measured in the carcase or in the feed efficiency experiments and BW measured in the ascites experiment (0.49) showed considerable genotype by environment interaction. (7) These results indicate that birds with high genetic potential for growth rate under normal temperature conditions have lower growth rate under cold-stress conditions due to ascites.

Animal Nutritional Physiological Phenomena↗

PubMed2005

Genetic parameters of ascites-related traits in broilers: effect of cold and normal temperature conditions.

(1) Ascites syndrome is a growth-related disorder of broilers that occurs more often in fast-growing birds and at low temperatures. The objective of this study was to estimate genetic and phenotypic correlations among ascites-related traits measured either under cold or under normal temperature conditions, and to estimate genetic correlations between ascites-related traits measured under cold and normal conditions. (2) Several traits related to ascites were measured on more than 4000 chickens under cold conditions and on more than 700 chickens under normal conditions. (3) The heritability estimates for body weight (BW) measured under cold and normal conditions were 0.42 and 0.50, respectively, for haematocrit value 0.46 and 0.17, respectively, and for ratio of right to total ventricular weight 0.45 and 0.12, respectively. (4) The genetic correlation between BW and haematocrit value under cold conditions was -0.23 and between BW and ratio of right to total ventricular weight -0.27. Under normal conditions, however, these genetic correlations were 0.55 and 0.50, respectively. (5) These results demonstrate that the heritability estimates of ascites-related traits as well as genetic correlations between ascites-related traits and BW depend on the temperature conditions under which animals are kept. (6) Strong positive genetic correlations (around 0.8) were observed between total mortality, fluid in the abdomen and ratio of right to total ventricular weight under cold conditions. The genetic correlation between ratio of right to total ventricular weight under cold and normal conditions was 0.91. (7) These results suggest that the ratio of right to total ventricular weight measured under normal temperature conditions might serve as a good indicator trait for ascites.

Animals↗

PubMed2005

Effect of age and housing system on genetic parameters for broiler carcass traits.

The effect of age and housing system on genetic parameters for BW and carcass traits was investigated. Traits were measured on broilers of different ages (48, 63, and 70 d). Birds in the 48 and 70 d groups were raised in group housing, whereas birds in the 63 d group were raised in the same housing up to 22 d and in individual cages between 22 and 63 d. Each group consisted of approximately 2,000 individuals from a single group of parents. Carcass, breast meat, abdominal fat, and back half were expressed as percentage of BW. The heritabilities of BW at 48, 63, and 70 d were 0.31, 0.26, and 0.19, respectively, and the heritabilities of back half percentage at 48, 63, and 70 d were 0.42, 0.38, and 0.21, respectively. For other carcass traits, heritabilities were in the same range in different age groups. A positive genetic correlation was found between BW and valuable parts of carcass (breast meat and back half) at 48 d; these relationships were negative at 70 d. The genetic correlation between BW and abdominal fat percentage at 70 d was higher than at 48 d. The increase in growth at 48 d was accompanied by increase in valuable parts; at 70 d it was accompanied by an increase in abdominal fat percentage. The genetic correlation of BW at 48 d between individual cage and group housing demonstrated a genotype by environment interaction for performance of birds, which has consequences for design of breeding schemes.

Aging↗

PubMed2005

Broiler breeding strategies using indirect carcass measurements.

The objective of the current study was to determine the consequences of using indirect carcass measurements on the genetic response and rate of inbreeding in broiler breeding programs. In the base breeding scheme, selection candidates were evaluated based on direct carcass measurements on relatives. The possibilities of using indirect carcass measurements were investigated in alternative breeding schemes. Three alternative schemes, including indirect and own performance information for carcass traits on selection candidates, were evaluated by deterministic simulation. In the first scheme, indirect carcass traits were measured on male selection candidates. In the second scheme, indirect carcass traits were measured on male selection candidates, and direct carcass traits were measured on relatives. In the third scheme, indirect carcass traits were measured on male and female selection candidates, and direct carcass traits were measured on relatives. In the base scheme, the genetic response for breast muscle percentage (BMP) was 0.3%, and the rate of inbreeding was 0.96% per generation. In the third alternative scheme, the response for BMP increased by 66.2% compared with the base scheme, and the rate of inbreeding decreased to 0.79% per generation. The improved genetic gain resulted from increased accuracy of selection. The use of own performance information for selection candidates reduced the rate of inbreeding in alternative schemes, which is desirable for long-term selection. The accuracy of the indirect carcass measurements had consequences on the response for BMP and the rate of inbreeding. In most cases, an accuracy of 30% was sufficient to result in a higher gain for BMP and a lower rate of inbreeding as compared with the base scheme.

Animals↗

PubMed2005

Genetic mapping of quantitative trait loci affecting susceptibility in chicken to develop pulmonary hypertension syndrome.

Pulmonary hypertension syndrome (PHS), also referred to as ascites syndrome, is a growth-related disorder of chickens frequently observed in fast-growing broilers with insufficient pulmonary vascular capacity at low temperature and/or at high altitude. A cross between two genetically different broiler dam lines that originated from the White Plymouth Rock breed was used to produce a three-generation population. This population was used for the detection and localization of quantitative trait loci (QTL) affecting PHS-related traits. Ten full-sib families consisting of 456 G2 birds were typed with 420 microsatellite markers covering 24 autosomal chromosomes. Phenotypic observations were collected on 4202 G3 birds and a full-sib across family regression interval mapping approach was used to identify QTL. There was statistical evidence for QTL on chicken chromosome 2 (GGA2), GGA4 and GGA6. Suggestive QTL were found on chromosomes 5, 8, 10, 27 and 28. The most significant QTL were located on GGA2 for right and total ventricular weight as percentage of body weight (%RV and %TV respectively). A related trait, the ratio of right ventricular weight as percentage to total ventricular weight (RATIO), reached the suggestive threshold on this chromosome. All three QTL effects identified on GGA2 had their maximum test statistic in the region flanked by markers MCW0185 and MCW0245 (335-421 cM).

Animals↗

PubMed2004

Detection and localization of quantitative trait loci affecting fatness in broilers.

A cross between 2 genetically different outcross broiler dam lines, originating from the White Plymouth Rock breed, was used to produce a large 3-generation broiler population. This population was used to detect and localize QTL affecting fatness in chicken. Twenty full-sib birds in generation 1 and 456 full-sib birds in generation 2 were typed for microsatellite markers, and phenotypic observations were collected for 3 groups of generation 3 birds (approximately 1,800 birds per group). Body weight, abdominal fat weight, and percentage abdominal fat was recorded at the age of 7, 9, and 10 wk. To study the presence of QTL, an across-family weighted regression interval mapping approach was used in a full-sib QTL analysis. Genotypes from 410 markers mapped on 25 chromosomes were available. For the 3 traits, 26 QTL were found for 18 regions on 12 chromosomes. Two genomewise significant QTL (P < 0.05) were detected, one for percentage abdominal fat at the age of 10 wk on chicken chromosome 1 at 241 cM (MCW0058 to MCW0101) with a test statistic of 2.75 and the other for BW at the age of 10 wk on chicken chromosome 13 at 9 cM (MCW0322 to MCW0110) with a test statistic of 2.77. Significance levels were obtained using the permutation test. Multiple suggestive QTL were found on chromosomes 1, 2, 4, 13, 15, and 18, whereas chromosomes 3, 7, 10, 11, 14, and 27 had a single suggestive QTL.

Abdomen↗

PubMed2004

Estimation of genetic parameters for fat deposition and carcass traits in broilers.

Abdominal and subcutaneous fat are regarded as the main sources of waste in the slaughterhouse. Fat stored intramuscularly is regarded a favorite trait related to meat quality. The objective of current study was to estimate genetic parameters for fat deposition in the 3 different parts of body and their relationships with other carcass traits. Traits were recorded for 1,752 females and 1,526 males from a meat-type chicken line. Heritability estimates for abdominal fat percentage, skin percentage as a measure of subcutaneous fat, and intramuscular fat percentage were 0.71, 0.24, and 0.08, respectively. Heritabilities of the other carcass traits were moderate to high (0.28 to 0.73). There was a high genetic correlation between abdominal fat weight and skin weight (0.54), whereas the genetic correlation between abdominal fat weight and intramuscular fat percentage was almost zero (0.02). The BW at 7 wk showed a positive genetic correlation with fat production traits, which were high for intramuscular fat percentage (0.87) and moderate for skin percentage (0.17) and abdominal fat percentage (0.13). Therefore carcass traits could be improved by selection for increased breast muscle and reduced abdominal fat without decreased intramuscular fat.

Abdomen↗

PubMed2002

Direct and maternal genetic effects for ascites-related traits in broilers.

The objective of the present study was to estimate heritabilities for ascites-related traits in broilers and to assess the importance of maternal genetic effects for these traits. Several traits related to ascites were measured on more than 4,000 broilers kept under cold conditions. Heritabilities were estimated using an animal model with a direct genetic effect and a model with direct and maternal genetic effects. Estimated heritabilities from the direct genetic effects model were 0.46 for hematocrit value, 0.42 for BW, 0.47 for right ventricular weight, 0.46 for total ventricular weight, 0.45 for ratio of right ventricular weight to the total ventricular weight, 0.32 for total mortality, and 0.18 for fluid accumulation in the heart sac. Maternal effects significantly influenced the traits BW, total ventricular weight, and total mortality. Direct and maternal heritabilities, respectively, for BW were 0.21 and 0.04, for total ventricular weights were 0.29 and 0.03, and for total mortality were 0.16 and 0.05. The heritability estimates for ascites-related traits and the significance of maternal genetic effects for most of these traits indicate that direct and maternal genetic effects play an important role in the development of the ascites syndrome.

Acclimatization↗