Denis Bastianelli

Sequential feeding using whole wheat and a separate protein-mineral concentrate improved feed efficiency in laying hens.

The effect of feeding nutritionally different diets in sequential or loose-mix systems on the performance of laying hen was investigated from 16 to 46 wk of age. Equal proportions of whole wheat grain and protein-mineral concentrate (balancer diet) were fed either alternatively (sequential) or together (loose-mix) to ISA Brown hens. The control was fed a complete layer diet conventionally. Each treatment was allocated 16 cages and each cage contained 5 birds. Light was provided 16 h daily (0400 to 2000 h). Feed offered was controlled (121 g/bird per d) and distributed twice (4 and 11 h after lights-on). In the sequential treatment, only wheat was fed at first distribution, followed by balancer diet at the second distribution. In loose-mix, the 2 rations were mixed and fed together during the 2 distributions. Leftover feed was always removed before the next distribution. Sequential feeding reduced total feed intake when compared with loose-mix and control. It had lower wheat (-9 g/bird per d) but higher balancer (+1.7 g/bird per d) intakes than loose-mix. Egg production, egg mass, and egg weight were similar among treatments. This led to an improvement in efficiency of feed utilization in sequential compared with loose-mix and control (10 and 5%, respectively). Birds fed sequentially had lower calculated ME (kcal/bird per d) intake than those fed in loose-mix and control. Calculated CP (g/bird per d) intake was reduced in sequential compared with loose-mix and control. Sequentially fed hens were lighter in BW. However, they had heavier gizzard, pancreas, and liver. Similar liver lipid was observed among treatments. Liver glycogen was higher in loose-mix than the 2 other treatments. It was concluded that feeding whole wheat and balancer diet, sequentially or loosely mixed, had no negative effect on performance in laying hens. Thus, the 2 systems are alternative to conventional feeding. The increased efficiency of feed utilization in sequential feeding is an added advantage compared with loose-mix and thus could be employed in situations where it is practicable.

Genetic parameters of product quality and hepatic metabolism in fattened mule ducks.

Genetic parameters of traits related to hepatic lipid metabolism, carcass composition, and product quality of overfed mule ducks were estimated on both parental lines of this hybrid: the common duck line for the maternal side and the Muscovy line for the paternal side. The originality of the statistical model was to include simultaneously the additive genetic effect of the common ducks and that of the Muscovy ducks, revealing a greater genetic determinism in common than in Muscovy. Plasma metabolic indicators (glucose, triglyceride, and cholesterol contents) were heritable, in particular at the end of the overfeeding period, and heritabilities increased with the overfeeding stage. Carcass composition traits were highly heritable in the common line, with values ranging from 0.15 for liver weight, 0.21 for carcass weight, and 0.25 for abdominal fat weight to 0.32 for breast muscle weight. Heritabilities of technological outputs were greater for the fatty liver (0.19 and 0.08, respectively, on common and Muscovy sides for liver melting rate) than for the pectoralis major muscle (between 0.02 and 0.05 on both parental sides for cooking losses). Fortunately, the processing industry is mainly facing problems in liver quality, such as too high of a melting rate, than in meat quality. The meat quality appraisal criteria (such as texture and cooking losses), usually dependent on pH and the rate of decline of pH, were also very lowly heritable. This study demonstrated that genetic determinism of meat quality and ability of overfeeding is not similar in the common population and in the Muscovy population; traits related to fattening, muscle development, and BW have heritability values from 2 to 4 times greater on the common line than on the Muscovy line, which is relevant for considering different selection strategies.

Intra- and interspecific differences in diet quality and composition in a large herbivore community.

Species diversity in large herbivore communities is often explained by niche segregation allowed by differences in body mass and digestive morphophysiological features. Based on large number of gut samples in fall and winter, we analysed the temporal dynamics of diet composition, quality and interspecific overlap of 4 coexisting mountain herbivores. We tested whether the relative consumption of grass and browse differed among species of different rumen types (moose-type and intermediate-type), whether diet was of lower quality for the largest species, whether we could identify plant species which determined diet quality, and whether these plants, which could be “key-food-resources” were similar for all herbivores. Our analyses revealed that (1) body mass and rumen types were overall poor predictors of diet composition and quality, although the roe deer, a species with a moose-type rumen was confirmed as an “obligatory non grazer”, while red deer, the largest species, had the most lignified diet; (2) diet overlap among herbivores was well predicted by rumen type (high among species of intermediate types only), when measured over broad plant groups, (3) the relationship between diet composition and quality differed among herbivore species, and the actual plant species used during winter which determined the diet quality, was herbivore species-specific. Even if diets overlapped to a great extent, the species-specific relationships between diet composition and quality suggest that herbivores may select different plant species within similar plant group types, or different plant parts and that this, along with other behavioural mechanisms of ecological niche segregation, may contribute to the coexistence of large herbivores of relatively similar body mass, as observed in mountain ecosystems.

Early lysine deficiency in young broiler chicks.

The carry-over effect of a pre-starter diet (0 to 3 days of age) deficient in lysine on subsequent growth and body composition (3 to 10 days) was examined in two experiments on male broiler chicks raised in cages. In experiment 1, lysine deficiency was applied from 3 to 10 days after providing a balanced pre-starter control feed (D+, 1.40% lysine) or a lysine deficient feed (D-) during the first 3 days. Three levels of deficiency (Axa0=xa00.63%, Bxa0=xa00.72%, Cxa0=xa00.82%) were tested. Growth and feed intake were higher in D+ than in D- chicks (xa0Pxa0<xa00.001). However, the feed conversion ratio from 3 to 10 days of age was higher in D+ chicks (xa0Pxa0<xa00.001); pre-starter and starter feeds interacted (xa0Pxa0<xa00.04) with the feed conversion of treatment D+/Axa0=xa02.07 being better than treatment D+/Axa0=xa02.61 (xa0Pxa0<xa00.05). This suggests that chicks deficient from hatching exhibit a relatively lower sensitivity to lysine deficiency than chicks started on a control diet. In experiment 2, performance, slaughter parameters and body composition were analysed at 3 and 10 days of age, in chicks having received a lysine deficient feed (D0, 0.72% lysine), a control feed (D+, 1.40% lysine) or having been pair fed with control feed adjusted to D0 intake (PF) from 0 to 3 days of age, and then fed D0 ad libitum from 3 to 10 days of age. At 3 days, PF chicks had a higher body weight (xa0Pxa0<xa00.05) than D0, and thus a better feed conversion. Body composition in relative values was little or not affected by dietary treatments, but the breast muscle weight at 3 days was higher in D+ and PF chicks compared with D0 (xa0Pxa0<xa00.05) and this effect was even accentuated at 10 days of age. The present work confirms that early nutrition can have subsequent consequences on the adjustment of fast growing broiler chicks to their nutritional conditions. It also suggests that breast muscle development is a more reactive parameter than whole body composition in this kind of experiments.

Detection of QTL controlling metabolism, meat quality, and liver quality traits of the overfed interspecific hybrid mule duck.

The mule duck, an interspecific hybrid obtained by crossing common duck (Anas platyrhynchos) females with Muscovy (Cairina moschata) drakes, is widely used for fatty liver production. The purpose of the present study was to detect and map single and pleiotropic QTL that segregate in the common duck species, and influence the expression of traits in their overfed mule duck offspring. To this end, we generated a common duck backcross (BC) population by crossing Kaiya and heavy Pekin experimental lines, which differ notably in regard to the BW and overfeeding ability of their mule progeny. The BC females were mated to Muscovy drakes and, on average, 4 male mule ducks hatched per BC female (1600 in total) and were measured for growth, metabolism during growth and the overfeeding period, overfeeding ability, and the quality of their breast meat and fatty liver. The phenotypic value of BC females was estimated for each trait by assigning to each female the mean value of the phenotypes of her offspring. Estimations allowed for variance, which depended on the number of male offspring per BC and the heritability of the trait considered. The genetic map used for QTL detection consisted of 91 microsatellite markers aggregated into 16 linkage groups (LG) covering a total of 778 cM. Twenty-two QTL were found to be significant at the 1% chromosome-wide threshold level using the single-trait detection option of the QTLMap software. Most of the QTL detected were related to the quality of breast meat and fatty liver: QTL for meat pH 20 min post mortem were mapped to LG4 (at the 1% genome-wide significance level), and QTL for meat lipid content and cooking losses were mapped to LG2a. The QTL related to fatty liver weight and liver protein and lipid content were for the most part detected on LG2c and LG9. Multitrait analysis highlighted the pleiotropic effects of QTL in these chromosome regions. Apart from the strong QTL for plasma triglyceride content at the end of the overfeeding period mapped to chromosome Z using single-trait analysis, all metabolic trait QTL were detected with the multitrait approach: the QTL mapped to LG14 and LG21 affected the plasma cholesterol and triglyceride contents, whereas the QTL mapped to LG2a seemed to impact glycemia and the basal plasma corticosterone content. A greater density genetic map will be needed to further fine map the QTL.

Editorial - Qualité des produits animaux de l’Indianocéanie : des recherches pour la valorisation des produits et la protection des consommateurs

Securite alimentaire et nutritionnelle, developpement economique regional, surete sa¬nitaire des aliments et protection des consommateurs… Ces defis sont fondamentaux pour le futur des populations des iles du sud-ouest de locean Indien – la Reunion, lile Maurice (et lile Rodrigues), Madagascar, les Comores, et les Seychelles –, tout autant que pour lensemble des pays du Sud. Les produits dorigine animale – viande, lait, pois¬son ou miel – contribuent a creer de la richesse et permettent de couvrir une partie des besoins alimentaires dans ces iles, alors quils sont traditionnellement issus delevages et dunites de transformation de petites tailles. Le reseau scientifique et technique QualiREG est dedie a lamelioration de la securite des aliments et au developpement de productions alimentaires de qualite dans les pays de locean Indien ; il rassemble plus de 60 organismes issus de locean Indien et de la region Afrique du Sud. Ces organismes partenaires sont non seulement des institutions de recherche ou des laboratoires danalyse et de controle, mais aussi des organismes den¬seignement superieur, des operateurs prives et des organisations regionales et internatio¬nales. Grâce au soutien du Conseil regional de la Reunion, de lEurope et de lEtat fran¬cais, QualiREG travaille depuis 2009 a mettre en mouvement les mondes scientifiques et economiques autour de la surveillance, de la recherche, de linnovation, du transfert, et de la formation. Formations, etudes de marche, enquetes epidemiologiques, surveil¬lance des denrees alimentaires, recherche et developpement, diffusion de linformation, analyses nutritionnelles, profils sensoriels, elaboration de guides de bonnes pratiques, et developpement de procedes de transformation innovants sont autant dactions et de resultats generes par QualiREG au profit des filieres agroalimentaires et des institutions de lIndianoceanie. Ce numero thematique de la Revue delevage et de medecine veterinaire des pays tropi¬caux est consacre a ces produits animaux elabores et consommes dans les iles de locean Indien. Il compile les actes des trois dernieres editions des journees scientifiques de Qua¬liREG qui se sont deroulees en 2012 et 2013 a la Reunion, et en 2014 a Madagascar. Les journees scientifiques permettent aux chercheurs de presenter leurs resultats a des pairs ainsi quaux operateurs economiques des filieres agroalimentaires de la region. Cette synthese met en avant les resultats des chercheurs qui consacrent leurs travaux a mai¬triser les dangers sanitaires qui leur sont associes, a explorer les modes de production, ou encore a revisiter les procedes de transformation traditionnels pour ameliorer leur conservation ou leur valeur marchande. Ce numero rassemble ainsi 21 communications scientifiques ayant trait aux productions animales et presentant des resultats de recherche dont la portee nous a semble depasser le cadre du reseau et meriter detre diffuses plus largement. Initialement presentees sous forme de resumes lors des journees scientifiques, les communications ont ete ici enrichies par leurs auteurs en developpant et en illustrant les resultats. Par ailleurs, certaines ont ete publiees ulterieurement dans des revues scientifiques sous forme darticles complets dont les references sont indiquees dans le texte. Les articles ont ete regroupes en trois sections. La premiere rassemble cinq etudes ayant trait a la transformation et a la conservation des produits carnes et halieutiques. Ces produits sont issus de filieres souvent traditionnelles mais pour lesquelles il existe un enjeu fort en matiere dinnovation technologique dans la perspective du developpement des agro-industries locales. La deuxieme section, composee de dix articles, illustre a quel point les questions de qua¬lite sanitaire demeurent prioritaires pour le futur des productions animales. Ces resul¬tats sont originaux dans leur description de la situation sanitaire difficile des iles de locean Indien. Ils montrent bien quil faudra intensifier les efforts de recherche pour mener la lutte contre les zoonoses tropicales, souvent negligees, transmises par les ali¬ments. Lemergence de bacteries resistantes aux antibiotiques presentes dans les produits animaux, ainsi que la forte prevalence de viandes contaminees par des residus de medi¬caments, antibiotiques ou hormones de synthese doivent alerter lensemble de la commu¬naute scientifique, ainsi que les operateurs economiques et les politiques pour proposer une strategie a long terme commune a toutes les iles. Enfin, la troisieme section presente six etudes portant sur la caracterisation et la valori¬sation de produits animaux. A linstar du miel, ces produits sont attaches a des territoires et a des savoir-faire uniques et presentent des caracteristiques organoleptiques origi¬nales, susceptibles detre protegees et reconnues par une labellisation dorigine. Nous vous livrons avec plaisir ce numero thematique qui montre, sil en est encore besoin, que la qualite des produits demeure un theme federateur et passionnant pour la recherche agronomique, ainsi quun levier de developpement pour les filieres agroalimentaires des pays du Sud. (Resume dauteur)