Growth characteristics and lipid distribution in two lines of chicken selected for low or high abdominal fat

1. This study shows the results of (a) fitting growth data to a Gompertz-Laird model and (b) fitting egg production per housed bird to a Grossman model, in a population of Castellana Negra hens. 2. The maximum growth point for males and females, respectively, occurred at 10.6 and 9.3 weeks and the estimated weights at maturity were 2852 and 1878 g. Growth curve parameters were lower than those of commercial lines and similar to reports of other unselected breeds. 3. The start of lay was at 23 weeks. Total egg production reached 163 at 52 weeks, with a persistency (length of constant production) of 3.4 weeks and a production maximum of 69%. The maximum rate of change segment of the laying curve started at 24.3 weeks of age, and the production maximum started at 5.8 weeks into lay. The rate of decline was 1.4% weekly. 4. The Castellana Negra breed belongs to the class of slow-growing light lines and egg production was 163 eggs per calendar year.

Section: Growthsupporting

confidence: 96%

Growth and lay modelling in a population of Castellana Negra native Spanish hens

Miguel

Asenjo

Ciria

et al. 2007

“…Reports describing the growth curve with a mathematical function suggest that the inflection point of the growth curve, that is, the end of the acceleration phase and the onset of the retardation phase, varies in the meat-type chickens between 6 and 9 weeks of age depending on selection traits used for their formation (Leclercq et al, 1989;Knížetová et al, 1991Knížetová et al, , 1995Mignon-Grasteau et al, 2000). In contrast, in the meat-type quail this was usually observed between 2 and 3 weeks of age (Marks, 1978;Anthony et al, 1991;Hyánková et al, 1998Hyánková et al, , 2001Hyánková et al, , 2002.…”

Section: Discussionmentioning

confidence: 82%

“…These data correspond with findings in chicken lines divergently selected for abdominal fat. According to Leclercq et al (1989), significant inter-line differences for both abdominal and extra-abdominal triglycerides were observed after 15 d of age, maximum divergence between lines occurred at 63 d of age, and subsequently these differences tended to diminish near sexual maturity. A similar disappearance of inter-line differences in fatness was reported also in the chicken lines divergently selected for VLDL (Whitehead et al, 1990).…”

Section: Carcase Compositionmentioning

confidence: 95%

“…These observations on fat and lean selection lines provided more insight into the physiology of excessive fatness and extended a practical tool for poultry breeders. In addition, correlated responses in the growth of lean and fat chickens (Leenstra and Pit, 1987;Leclercq et al, 1989) implied that genetical changes in the growth pattern could be the primary mechanism causing the relatively high fat content of broilers selected solely for body weight (BW). Nevertheless, the direct relationship between the genetical manipulation of the growth curve and the increase of body fat content has not been unambiguously clarified.…”

Section: Introductionmentioning

confidence: 99%

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Divergent selection for shape of growth curve in Japanese quail. 4. Carcase composition and thyroid hormones

Hyánková

Novotná

Darras

2008

1. Changes in the relative weights of carcase, abdominal fat, breast and leg muscles, and plasma thyroid hormone concentrations occurring during the first 6 weeks of postnatal growth were analysed in males of HG and LG lines divergently selected for high and low relative body weight (BW) gain between 11 and 28 d of age, respectively, and constant adult BW. 2. The second week of postnatal life was a critical age at which the HG males exhibited a relatively faster growth in comparison to their LG counterparts and permanently exceeded LG males in the percentage by weight of carcase, breast and leg muscle. A higher production of muscle tissues was associated with lower accumulation of abdominal fat before sexual maturity. 3. In general, the plasma T(3) level of HG quail exceeded that of LG quail. Nevertheless, significant differences were found only at 14, 21 and 28 d of age, that is, in the period during which the highest inter-line differences in relative growth rate were noted. Also the T(3)/T(4) ratio followed a similar trend while plasma T(4) level showed no clear and consistent inter-line differences. 4. The results suggest that the selection for the shape of the growth curve, like the selection for body fat, modifies the carcase quality owing to shortening/prolongation of the acceleration growth phase. Individuals with a short acceleration phase of the growth curve are characterised by low carcase quality during the fattening period.

“…Maximum adult weight was significantly greater for ducks from the selected generations (JV+ 3 and JV+ 4) but age at maximum growth rate was slightly delayed (1-3 to 1-8 d). Leclercq et al (1989) compared growth curves in 2 lines of chickens divergently selected for high or low abdominal fat. They showed that lean chickens exhibited a slower growth rate from hatching to 63 d of age and that maximum growth rate was reached later than in fat chickens.…”

Section: Discussionmentioning

confidence: 99%

Effects of selection, over three and four generations, on meat yield and fatness in Muscovy ducks

Baéza¹,

Carville²,

Salichon³

et al. 1997

Self Cite

1. Two experiments were undertaken to analyse the effects of selection for lowering carcase fatness and improving meat yield of Muscovy ducks. The control generation N and the selected generations N + 3 and N + 4 of the same heavy line (Grimaud) were reared under similar conditions. 2. We compared growth, carcase characteristics, chemical composition of breasts and plasma concentrations of very low density lipoproteins (VLDL), triglycerides and phospholipids. 3. Selection induced an increase of body weight (+8% to 10% at slaughter age), a decrease of abdominal fat percentage (-10%) and an improvement of breast and thigh plus shank yields (+3% to 7% and +4% respectively). 4. The lipid content of breast meat decreased in the selected ducks (-14% to -20%), particularly phospholipids and triglycerides. Breasts appeared paler and less red which suggested modifications of muscular fibre composition. 5. We found no significant correlations between plasma VLDL, triglyceride and phospholipid concentrations and carcase fatness. It therefore seems difficult to use these variables as selection criteria for lowering carcase fatness of Muscovy ducklings.