Family Differences (family + difference)

Distribution by Scientific Domains

Selected Abstracts

Differences in Growth and Nutrient Efficiency Between and Within Two Channel Catfish Ictalurus punctatus Strains

A 6-wk growth study was conducted comparing fingerling (mean weight = 24.7 g) USDA103 strain channel catfish Ictalurus punctatus to Norris strain channel catfish in an effort to determine strain differences in growth and nutrient efficiency. Variability within strains also was assessed by randomly selecting four families from each strain for comparison. On average, USDA103 fish gained significantly (P < 0.05) more weight (51.2 vs. 31.7 g) and length (4.7 vs. 4.1 cm) compared to Norris strain catfish. Significantly (P < 0.05) greater feed consumption (56.6 vs 41.3 g) and feed efficiency (95.7 vs. 89.9) for USDA103 catfish were also observed. Family differences in weight and length gain and feed intake were significant (P < 0.05) among USDA103 families; whereas, only differences in feed intake and feed efficiency were significant (P < 0.05) among Norris families. Nitrogen retention was higher (P < 0.05) for the Norris strain catfish (35.6%) relative to the USDA103 strain average (31.0%). The results of this study reiterate the superior growth and feed efficiency of the USDA103 strain of channel catfish. Observed differences among USDA103 families suggest that further improvements in weight gain can be made through selective breeding; however, improvements in feed and protein efficiency may be difficult. [source]

Analysis of the incidence of infectious pancreatic necrosis mortality in pedigreed Atlantic salmon, Salmo salar L., populations

D R Guy
Abstract A total of 77 124 Atlantic salmon post-smolts, representing 197 full-sib families produced by 149 males and 197 females, experienced a field challenge from infectious pancreatic necrosis virus (IPNV), following transfer to three separate seawater sites. The first IPN mortality was observed 45 days after transfer, and the duration of the epidemic varied between 37 and 92 days among sites. Mortalities were traced to their parental families by PIT (Passive Integrated Transpondes) tag records and DNA genotyping. Full-sib family mean incidence of mortality was calculated for each family on each site. Heritabilities were estimated based on the heterogeneity of chi-square using incidence within half-sib families and the variance in incidence among full-sib families, both on the observed and underlying liability scale. The observed correlation among families across sites was used to estimate genetic correlations. The overall mortality rate was 10.8%, with only small differences between sites, ranging from 10.3% to 11.9%. Heritabilities on the liability scale were found to be moderate to strong, and ranged between 0.24 and 0.81, with a pooled estimate of 0.43, greater than is typically associated with disease traits. Genetic correlations among sites were all substantial, between 0.71 and 0.78, and indicated that a substantial component of the genetic variation displayed within sites was common to all. The results show that field challenges can yield very good genetic information on family differences in resistance, especially when replicated over sites, which may then be developed for use in selection for breeding strains of Atlantic salmon with greater resistance to IPN. [source]

Is Constitutional Politics like Politics ,At Home'?

The Case of the EU Constitution
A large number of delegates from different institutional levels within the EU have achieved a remarkable consensus on a draft constitution. Has this consensus been made possible because the nationally predominant left,right divide was only weakly present during the deliberations of the delegates? Left,right differences have been analysed by means of a content analysis on submitted documents during the European Convention. The data analysis confirms our assumption that the left,right distinction was relevant, although not very dominant. The draft constitution did not take a mean position on left and right issues, but in fact puts more emphasis on substantial goals related to both left and right, giving an equal weight to both anti-poles. However, if we exclude the Charter of Human Rights, the draft constitution appears to be strongly tilted to the right. The analysis also shows that party family differences did affect the process of coalition building during the Convention, since more than half of all documents have been submitted together with at least one member of the same party family and/or with one family member close by. Our analysis also indicates that the process of consensus building was enhanced by the absence of many extremist and new parties during the Convention. This may have enhanced agreement on the Constitution, but later it became problematic for the domestic democratic process and for the acceptance of the Constitution in some countries, such as France and the Netherlands, especially since some of the excluded parties have actively and successfully mobilised voters to vote against the Constitution. [source]

Sex, age, and family differences in the chemical composition of owl monkey (Aotus nancymaae) subcaudal scent secretions

Edith A. MacDonald
Abstract Numerous behavioral studies have shown that animals use olfactory cues as inbreeding avoidance or kin avoidance mechanisms, implying that scent is unique to families. However, few studies have analyzed the chemical profile of a scent and ascertained the messages that are conveyed in scent secretions. Owl monkeys (Aotus nancymaae) are socially monogamous primates that utilize scent when interacting with foreign conspecifics. This suggests there is a difference in the chemical composition of scent marks. We chemically analyzed sub-caudal gland samples from three families of captive owl monkeys (Aotus nancymaae). Samples were analyzed by capillary GC-MS and relative retention time and fragment pattern was compared with known standards. Gland samples were high in large plant-based shikikate metabolites and fatty ketones; alcohols, acids, and acetates were virtually absent. Gender, age, and family could be reliably classified using discriminant analysis (92.9, 100, and 100%, respectively). Female scent profiles were greater in concentration of aromatic plant metabolites, possibly the result of a different diet or physiological differences in female metabolism as compared to male. Offspring of adult age still living in their natal group showed a less complex chemical profile than their parents. Finally, each family had its own unique and complex chemical profile. The presence of family scent may play a role in mediating social interactions. Am. J. Primatol. 70:12,18, 2007. 2007 Wiley-Liss, Inc. [source]