R. Rouvier

Female-specific DNA sequences in geese

1. The OPAE random primers (Operon Technologies, Inc., CA) were used for random amplified polymorphic DNA (RAPD) fingerprinting in Chinese, White Roman and Landaise geese. One of these primers, OPAE-06, produced a 938-bp sex-specific fragment in all females and in no males of Chinese geese only. 2. A novel female-specific DNA sequence in Chinese goose was cloned and sequenced. Two primers, CGSex-F and CGSex-R, were designed in order to amplify a 912-bp sex-specific polymerase chain reaction (PCR) fragment on genomic DNA from female geese. 3. It was shown that a simple and effective PCR-based sexing technique could be used in the three goose breeds studied. 4. Nucleotide sequencing of the sex-specific fragments in White Roman and Landaise geese was performed and sequence differences were observed among these three breeds.

Genetics and selection of mule ducks in France: a review

Duck breeding in France is directed mainly towards ‘foie gras’ (duck fatty liver) production. Nowadays the roasted duck, produced from the pure Muscovy, is economically a less important industry. About 95% of foie gras production comes from force-fed mule duck, the remaining 5% being from the Muscovy duck. After an overview of the French economical and technical context of this production, the paper will focus on the genetic aspects of the mule duck, at the level of theoretical knowledge and considering practical applications for selection. As the mule duck is an infertile hybrid between a female common duck (Anas Platyrhynchos) and a Muscovy drake (Cairina moschata), selection approaches are carried out on both parental strains. But to implement selection, genetic parameters (heritability and genetic correlations) and cross-breeding parameters (direct and maternal additive genetic effects, heterosis effect) need to be known. Our review covers both the reproductive mule parental traits, either in pure strain or in cross-breeding, with main results on the dam side for laying, fertility and hatchability and also considers the mule productive traits, such as growth, feather colour, behaviour, feed efficiency, body composition, force-feeding ability and products quality. Genetic variability of mule duck traits can be established from estimates on either the dams side, on the sires side, or on both sides simultaneously. This review represents a comparison of fatty duck selection, which is operated by three major private French companies, with outlines of the breeding scheme specificity.

Heritabilities and genetic correlations of body weights and feather length in growing Muscovy selected in Taiwan

1. Heritabilities and genetic correlations in the base population of a closed strain of Muscovy duck, moderately selected for body weight at 10 weeks of age, have been estimated from the data of 9 successive generations for the following traits: male and female body weight at 10 and 18 weeks of age (BW10m, BW18m, BW10f, BW18f) and length of the 8th primary feather at 10 weeks of age (F110m, F110f). 2. Multivariate REML with an animal model was used, pooling data from the 9 generations (3283 and 3289 male and female offspring respectively). The same trait expressed in male and female was considered as 2 different traits. 3. The 8th primary feather was longer in females than in males by 6% to 22% at 10 weeks of age. Body weight was heavier in males than in females by 42% to 58% at 10 weeks of age and by 57% to 75% at 18 weeks of age. 3. The heritability estimates for body weight traits showed moderate values, being a little higher for females than for males at the same age, increasing with age from h2=0.24 at BW10m to h2=0.43 at BW18f. 4. The heritability estimates for feather length showed that a greater response would be obtained in selection for male feather length (h2=0.37) than for female length (h2=0.14). Both have high genetic correlations with body weight so they could be indirectly improved. 5. Heritabilities of the difference in body weights between males and females at 10 weeks (h2=0.07) and 18 weeks of age (h2=0.10) were small, as well as for feather length (h2=0.10). It would probably be difficult to modify sexual dimorphism in body weight through selection. 6. Genetic correlations between BW10m, BW18m and BW10f, BW18f were respectively r(g)=0.77 and r(g)=0.80. They were larger for body weight at the same ages between males and females, r(g)=0.90 (r(g)=0.88 between F110m and F110f). Body weight in males and females at the same age should be better considered as 2 different traits in a selection programme. 7. The cumulated predicted genetic gains expressed per unity of the genetic standard deviation (sigma(g)) over the 8 generations of selection were 1.3 sigma(g) and 1.4 sigma(g) respectively for the BW10m and BW10f. The predicted correlated responses were 1.2 sigma(g) for body weights at 18 weeks of age, 0.9 sigma(g) and 0.7 sigma(g) for F110f and F110m respectively.

AFLP fingerprinting for paternity testing in ducks

1. The accuracy and reproducibility of AFLP fingerprinting was investigated in the duck (Anas Platyrhynchos), using a multicolour fluorescent labeling technique. The fluorescent labelling fragments were separated on a capillary electrophoresis-base ABI PRISM 3100 Genetic Analyzer. 2. A total of 337 AFLP peaks with 103 of them being polymorphic markers were generated by 16 sets consisting of EcoRI/TaqI primer pair combinations. The number and size range of AFLP polymorphisms detected per primer pair varied from 3 to 11 and 58 to 290 bp, respectively. About 30·6% (103/337) of AFLP peaks were detected polymorphisms, with an average of 6·4 polymorphic markers per primer pair. 3. The clear polymorphic peaks were amplified with EcoR+AC/Taq+AC primer combinations. The AFLP peaks showed high reproducibility. From the family testing, we found that the fingerprints of all the offspring were derived from one or other parent. Therefore, we conclude that AFLP fingerprinting might be a suitable method for duck paternity testing.

Selection responses in duration of fertility and its consequences on hatchability in the intergeneric crossbreeding of ducks.

1. From 1992 to 2003, selected (S) and control lines (C) of the laying Brown Tsaiya duck (Anas platyrhynchos) were simultaneously maintained under the same standardised conditions of feeding and management. 2. The selection objective was to increase the number of fertile eggs after a single artificial insemination (AI) with pooled Muscovy semen. From generations G1 to G11, 2452 and 2022 female ducks, in S and C lines, respectively, were measured and recorded. In the S line, the percentage selected varied between 20·2 and 34·3% in females and between 7·2 and 20·8% in males. 3. Selection for number of fertile eggs had a correlated effect of increasing the parameter τ of the logistic curves which fitted the daily variations (d 2 to 15) in fertility or hatchability on the basis of eggs set. The differences S − C for the estimates of the times of half maximal fertility and hatchability increased by 0·41 and 0·37 d per generation between G1 and G11, respectively. 4. The highest increases of fertility per day rates after a single AI were observed between d 5 and 11. Moreover, in the selected line, fertility rate was higher than, or equal to, 90% in d 2 from G8. The same tendencies were observed for the changes in the evolution of hatchability on the basis of eggs set. 5. Selection increased fertility and hatchability according to the egg set rates, especially for d 2 to 8 after AI. Hatchability of fertile eggs was not impaired, confirming that selection for one AI per week was possible in this strain of laying ducks.

Duck (Anas platyrhynchos) linkage mapping by AFLP fingerprinting

Amplified fragment length polymorphism (AFLP) with multicolored fluorescent molecular markers was used to analyze duck (Anas platyrhynchos) genomic DNA and to construct the first AFLP genetic linkage map. These markers were developed and genotyped in 766 F2 individuals from six families from a cross between two different selected duck lines, brown Tsaiya and Pekin. Two hundred and ninety-six polymorphic bands (64% of all bands) were detected using 18 pairs of fluorescent Taq I/Eco RI primer combinations. Each primer set produced a range of 7 to 29 fragments in the reactions, and generated on average 16.4 polymorphic bands. The AFLP linkage map included 260 co-dominant markers distributed in 32 linkage groups. Twenty-one co-dominant markers were not linked with any other marker. Each linkage group contained three to 63 molecular markers and their size ranged between 19.0 cM and 171.9 cM. This AFLP linkage map provides important information for establishing a duck chromosome map, for mapping quantitative trait loci (QTL mapping) and for breeding applications.

Breeding and genetics of waterfowl

Genetic parameters of traits of interest in ducks and geese are reported. Recent achievements of research, specially to improve the Brown Tsaiya laying duck; the intergeneric crossbreeding in duck; the meat ducks Pekin and Muscovy; the goose reproduction ability; the meat and fatty liver production in geese and ducks were analysed. A linear genetic selection index based on MT-BLUP animal model of breeding values with objectives to maintain body weight, egg weight at current levels, to increase egg shell strength and egg number, used for four generations in Brown Tsaiya laying ducks was evaluated. A seven generations selection experiment was successful in increasing the duration of fertility of Brown Tsaiya female ducks by artificial insemination with pooled Muscovy semen. The genetic parameters of growth and laying traits in a selected Muscovy line in Taiwan were estimated. Favourable genetic trends for body weight at given age, without decreasing egg production, were found in this selected Muscovy line. The selection of grandparent stocks (White Tsaiya and Pekin) for white plumage mule ducks in Taiwan was efficient. The genetic parameters of laying and gosling production traits of Landaise geese and of a White plumage goose strain, bred in two systems, respectively outdoors with natural photoperiodism and in indoors with short daylight conditions were reported. The more advantageous system in selecting for laying traits in geese is discussed. Fatty liver weight was found to be highly heritable in geese and male Muscovy ducks. The genetic parameters of overfed mule duck traits were estimated in the Pekin dam population. It is concluded that future research should focus on biotechnology, quantitative trait loci detection and genome analysis.

Heritabilities and genetic correlations of laying performance in muscovy ducks selected in Taiwan

1. Genetic parameters in the base population of a closed experimental strain of Muscovy ducks, selected for body weight at 10 weeks of age, were estimated from data in 8 successive generations, for the following traits: age at first egg (AGE1EGG), total number of eggs laid at 40 and 52 weeks of age (NEGG40 and NEGG52), number of eggs laid during 15 and 22 weeks in the first laying cycle (NEGG15W and NEGG22W), and their Box–Cox transformed data. 2. The method of multi-trait restricted maximum likelihood with an animal model was used to estimate genetic parameters. Only the results obtained with non-transformed data are shown. 3. Heritability estimates for laying performance showed moderate values, increasing little with age: 0·20 ± 0·03 (AGE1EGG), 0·23 ± 0·03 (NEGG40), 0·27 ± 0·03 (NEGG52), 0·20 ± 0·03 (NEGG15W), and 0·22 ± 0·03 (NEGG22W). 4. Genetic correlations between laying traits were high. Genetic correlation between AGE1EGG and egg number was negative, it was positive between total numbers of eggs at 40 and 52 weeks and egg numbers in the first laying cycle. 5. Body weight at 10 weeks of age exhibited positive genetic correlations (0·46 ± 0·06) with age at first egg and negative with egg production traits (− 0·28 ± 0·06 to − 0·41 ± 0·06). 6. The cumulated predicted genetic gains, after 7 generations of selection, expressed per genetic standard deviation unit (σ g) were 0·06σ g, 0·07σ g, 0·17σ g, 0·23σ g, and 0·25σ g for AGE1EGG, NEGG40, NEGG52, NEGG15W, and NEGG22W, respectively. 7. Selecting Muscovy ducks to improve laying in Taiwanese climatic conditions would be possible using the number of eggs laid up to 52 weeks of age as the selection criterion. Because unintended selection effects for laying traits were present, the selection experiment for body weight at 10 weeks of age was not antagonistic with laying traits.

Heritabilities for duration of fertility traits in Brown Tsaiya female ducks (anas platyrhynchos) by artificial insemination with pooled muscovy (cairina moschata) semen

1. Fertility traits in 348 Brown Tsaiya female ducks were analysed following intergeneric crossbreeding by artificial insemination (AI) with pooled Muscovy semen. The females descended from 18 sires and 107 dams. At 50 weeks of age, the ducks were intra-vaginally inseminated once with 0.03 ml of pooled Muscovy semen. Subsequently eggs were collected for 15 d and set for incubation up to candling 10 d later. 2. Average fertility decreased from 87% at day 2 after AI to 53% at day 6 and less than 7% from day 10 onwards. 3. The best criterion of selection for duration of fertility seems to be the number of fertile eggs from 2nd day up to the 15th day after AI. Heritability estimates for this trait were hs2 = 0.29 +/- 0.18., hD2 = 0.38 +/- 0.22.

Genetic parameters of some growth and egg production traits in laying Brown Tsaiya (Anas platyrynchos)

Cinq cent trente-sept femelles de la race locale de cane Tsaiya Brune a Taiwan, issues de 156 meres, 40 peres, 4 regions de Taiwan (origine des peres), nees dans 5 lots d’eclosion, sont utilisees dans cette etude, 15 caracteres sont etudies. Les poids des adultes (âge : 30 semaines) sont de 1397 ± 120 g. Les valeurs moyennes des caracteres mesures sont les suivantes : âge au le 1er œuf, 126 ± 11 j. Pour les nombres d’oeufs pondus aux âges de 245, 280 et 360 jours, on a respectivement 107 ± 13, 139 ± 15, 207 ± 26. Pour l’epaisseur de la coquille 0,37 ± 0,02 mm et pour sa solidite, 3,8 ± 0,5 kg/cm2. Les poids de l’oeuf, respectivement aux âges de 30 et 40 semaines sont 64,2 ± 4,3 g et 67,8 ± 4,3 g. Les parametres genetiques ont ete calcules: estimation des heritabilites a partir des composantes pere (formule, voir document attache) et mere (formule, voir document attache) de la variance. Les poids corporels aux âges de 8, 16, 20, 30 et 40 semaines presentent une variabilite genetique additive forte (formule, voir document attache). Pour le poids de l’oeuf a 30 et 40 semaines d’âge, (formule, voir document attache). Pour les caracteres de production d’oeufs, les valeurs de (formule, voir document attache) sont faibles et s’accroissent avec l’âge : (formule, voir document attache). Par contre les heritabilites calculees a partir des composantes meres de la variance sont significatives : (formule, voir document attache). L’existence d’une variabilite genetique non additive pour ces caracteres conduira a envisager une selection de souches et leur croisement.