Effect of dietary supplementation with algae extracts on growth performance and caecal microbiota of broiler chickens.

1. The objective of this study was to test the dose response of dietary supplementation with algae extracts rich in marine-sulphated polysaccharides (MSP1 and MSP2) on the growing performance, body composition at slaughter and caecal microbiota of broiler chickens.2. Male broiler Ross 308 chicks 1-d-old were distributed into eight groups, a control group (unsupplemented), four groups supplemented with increasing doses of algae extract MSP1 (40, 81, 121 and 162 g/ton feed) and three groups supplemented with increasing doses of algae extract MSP2 (40, 81 and 162 g/ton feed). Each group comprised six pens of 56 chickens.3. All chickens were reared under challenging conditions, i.e. high rearing density of 42 kg/m2, fed growing and finishing diets containing, palm oil, rye and high levels of wheat and subjected to short daily fasting periods. The growth performance was recorded during rearing. At 10, 22 and 31 d of age, 12 chickens per group were euthanised to collect the caecal contents and determine microbiota composition and short-chain fatty acid levels. At d 35, the quality of litter and the condition of feathers, footpads and tarsals were scored. At d 36, 7 chickens per pen were slaughtered under commercial conditions to determine carcass composition and breast meat quality (ultimate pH and colour).4. Algal extract MSP1 increased the weight of the caeca and butyrate concentration in the caeca at d 22 (p ≤ 0.05). It increased the ultimate pH of breast fillet measured after slaughter at d 36 (p ≤ 0.05). Moreover, the group receiving 162 g/t MSP1 had a more diverse microbiota at d22. However, algal extract MSP2 had negligible effect on the different measured parameters.

Qualitative market segmentation of broiler grillers by using alternative proteins to soybeans and lipid sources in feeding programmes.

1. The aim of the present study was to investigate increasing amount of n-3 fatty acids (FA) in common edible chicken meat cuts by testing different levels of extruded linseeds (LS) and rapeseed oil in growing and finishing diets. Another challenge was to replace a part of soybean meal by faba beans.2. For that purpose, 3168, one-day-old Hubbard JV15 strain chickens were distributed into six groups: R1 = control diet, R2 = 3% then 5% LS, R3 = 4% then 6% LS, R4 = 5% then 7% LS, R5 = 3% then 5% LS and a low amount of soybean meal in the finishing diet and R6 = 3% then 5% LS and no soybean meal in the finishing diet. The growing performance was recorded throughout the trial. At 30 days of age, all chickens were slaughtered in a commercial slaughter plant at an average weight of 1322 g, to mirror the production of low body weight 'broiler griller' birds commonly available for export markets. Thirty carcases per group were processed to determine cut yields. The edible parts from each half carcase were removed to determine the chemical composition and fatty acid composition of meat with skin. The sensorial quality of thighs was evaluated for 20 carcases per group, after roasting. The environmental and economic impacts of the feeding programmes were further evaluated.3. This study showed that it was possible to replace a part of the soybean meal in finishing diet by faba beans and to enrich meat with n-3 FA of broiler meat portions without altering growth performance, carcase composition and sensorial quality of meat. The environmental impact was reduced by these dietary interventions, whereby climate change parameters, expressed as kg CO2 eq./T, and phosphorus and fossil energy consumption were lower, but the land occupation was increased. The extra feed cost was +3 to +8% for groups fed R2 to R6 compared to the control group R1.

Multi-tissue transcriptomic study reveals the main role of liver in the chicken adaptive response to a switch in dietary energy source through the transcriptional regulation of lipogenesis.

BACKGROUND: Because the cost of cereals is unstable and represents a large part of production charges for meat-type chicken, there is an urge to formulate alternative diets from more cost-effective feedstuff. We have recently shown that meat-type chicken source is prone to adapt to dietary starch substitution with fat and fiber. The aim of this study was to better understand the molecular mechanisms of this adaptation to changes in dietary energy sources through the fine characterization of transcriptomic changes occurring in three major metabolic tissues - liver, adipose tissue and muscle - as well as in circulating blood cells. RESULTS: We revealed the fine-tuned regulation of many hepatic genes encoding key enzymes driving glycogenesis and de novo fatty acid synthesis pathways and of some genes participating in oxidation. Among the genes expressed upon consumption of a high-fat, high-fiber diet, we highlighted CPT1A, which encodes a key enzyme in the regulation of fatty acid oxidation. Conversely, the repression of lipogenic genes by the high-fat diet was clearly associated with the down-regulation of SREBF1 transcripts but was not associated with the transcript regulation of MLXIPL and NR1H3, which are both transcription factors. This result suggests a pivotal role for SREBF1 in lipogenesis regulation in response to a decrease in dietary starch and an increase in dietary PUFA. Other prospective regulators of de novo hepatic lipogenesis were suggested, such as PPARD, JUN, TADA2A and KAT2B, the last two genes belonging to the lysine acetyl transferase (KAT) complex family regulating histone and non-histone protein acetylation. Hepatic glycogenic genes were also down-regulated in chickens fed a high-fat, high-fiber diet compared to those in chickens fed a starch-based diet. No significant dietary-associated variations in gene expression profiles was observed in the other studied tissues, suggesting that the liver mainly contributed to the adaptation of birds to changes in energy source and nutrients in their diets, at least at the transcriptional level. Moreover, we showed that PUFA deposition observed in the different tissues may not rely on transcriptional changes. CONCLUSION: We showed the major role of the liver, at the gene expression level, in the adaptive response of chicken to dietary starch substitution with fat and fiber.

Generation and evaluation of typical meteorological year datasets for greenhouse and external conditions on the Mediterranean coast.

A typical meteorological year (TMY) represents the typical meteorological conditions over many years but still contains the short term fluctuations which are absent from long-term averaged data. Meteorological data were measured at the Experimental Station of Cajamar 'Las Palmerillas' (Cajamar Foundation) in Almeria, Spain, over 19 years at the meteorological station and in a reference greenhouse which is typical of those used in the region. The two sets of measurements were subjected to quality control analysis and then used to create TMY datasets using three different methodologies proposed in the literature. Three TMY datasets were generated for the external conditions and two for the greenhouse. They were assessed by using each as input to seven horticultural models and comparing the model results with those obtained by experiment in practical trials. In addition, the models were used with the meteorological data recorded during the trials. A scoring system was used to identify the best performing TMY in each application and then rank them in overall performance. The best methodology was that of Argiriou for both greenhouse and external conditions. The average relative errors between the seasonal values estimated using the 19-year dataset and those using the Argiriou greenhouse TMY were 2.2 % (reference evapotranspiration), -0.45 % (pepper crop transpiration), 3.4 % (pepper crop nitrogen uptake) and 0.8 % (green bean yield). The values obtained using the Argiriou external TMY were 1.8 % (greenhouse reference evapotranspiration), 0.6 % (external reference evapotranspiration), 4.7 % (greenhouse heat requirement) and 0.9 % (loquat harvest date). Using the models with the 19 individual years in the historical dataset showed that the year to year weather variability gave results which differed from the average values by ± 15 %. By comparison with results from other greenhouses it was shown that the greenhouse TMY is applicable to greenhouses which have a solar radiation transmission of approximately 65 % and rely on manual control of ventilation which constitute the majority in the south-east of Spain and in most Mediterranean greenhouse areas.

Is it possible to increase the n-3 fatty acid content of eggs without affecting their technological and/or sensorial quality and the laying performance of hens?

The aim of this study was to increase the n-3 fatty acid (n-3 FA) content of eggs without affecting their sensorial and/or technological properties or the laying performance of hens. Laying hens from line 477 were divided into 5 groups corresponding to 5 different diets over the laying period: control diet (C) and diets containing extruded linseed with a high level of fibre (ELHF), extruded linseed with a low level of fibre (ELLF), microalgae, or a combination of 75% ELLF and 25% MA (ELLF+MA). Dietary enrichment with n-3 FA had no effect on the laying performance, hen body weight or egg white viscosity. The egg yolks produced by hens fed the diet containing microalgae were redder than egg yolks from the other groups, suggesting the presence of red pigments in the microalgae preparation. However, the colour difference was low and not perceptible to the human eye. Moreover, colour measurement of egg yolks by sensorial analysis panellists using the Roche colour fan did not reveal a diet effect on this parameter. Egg yolk lipid content was not affected by diet. The egg yolk of hens fed on diets containing linseed and/or microalgae had greater n-3 FA content (×2.5 to 2.9 compared to group C). Linseed mainly increased the linolenic acid content (×3.0 to 3.4 compared to group C) and the microalgae increased the LC n-3 FA content (×4.1 compared to group C). Dietary enrichment with n-3 FA had no effect on the sensorial quality of shell cooked eggs except for the "unusual flavour" criterion for which the score was higher for the MA group compared to the other groups and corresponded to a fishy flavour.

Is it possible to increase n-3 fatty acid content of meat without affecting its technological and/or sensory quality and the growing performance of chickens?

The aim of this study was to increase the content of n-3 fatty acids (FA) of meat without affecting its sensory and/or technological properties or the growth performance of chickens reared under standard conditions. Male chickens, Ross 308, were distributed into 5 groups corresponding to 5 different diets for the growing and finishing periods: control (T), containing extruded linseeds exhibiting high concentration of fibre (ELHF), extruded linseeds exhibiting low concentration of fibre (ELLF), microalgae, or an association of 75% ELLF and 25% MA (ELLF+MA). The diet containing microalgae induced a decrease in feed consumption without affecting growth rate. Chickens exhibited a lower feed conversion ratio than the other groups for the growing and finishing periods but also the whole rearing period. The use of linseeds in diets had no effect on the growth performance of chickens in comparison to the control group. The dietary enrichment with n-3 FA had few effects on carcass composition or the ultimate pH and colour of breast meat. The microalgae increased the meat susceptibility to oxidation. The lipid content of breast meat was not affected by the diets. The breast meat of chickens fed on diets containing linseeds and/or microalgae had greater n-3 FA content (2.4 to 3.9 times higher than group T). The linseeds and microalgae mainly increased the contents in linolenic acid and long chain n-3 FA, respectively. Dietary enrichment with n-3 FA had no effect on the sensory quality of fillets whereas the thighs of the MA group exhibited the lowest score for the flavour "chicken" and the greatest score for the flavour "abnormal" corresponding to a fish flavour.

Effects of dietary enrichment with n-3 fatty acids on the quality of raw and processed breast meat of high and low growth rate chickens.

1. The enrichment of raw poultry meat with n-3 fatty acids (n-3 FA) has been investigated in detail, particularly in high growth rate genotype standard broiler chickens, whereas low growth rate genotype Label Rouge chickens have received less attention. With the increased development of processed poultry products, it is necessary to ensure that the nutritional and sensory quality of meat enriched with n-3 FA is not affected by processing. 2. Two experiments were undertaken for this purpose. In the first experiment, 696 male Ross 708 chickens were reared under standard conditions, and in the second, 750 male JA 657 chickens were reared under Label Rouge conditions. All birds received the same starting and growing diets containing palm and soya oils in each experiment. Birds were distributed into three groups from 21 or 57 d of age for standard and Label Rouge chickens, respectively, and given a control, linseed oil or extruded linseed diet. Diets were also supplemented with vitamin E (100-200 mg/kg). Birds were slaughtered at 56 or 84 d of age for standard and Label Rouge chickens, respectively. A total amount of 60 kg of breast meat from each group was processed into white cured-cooked meat. 3. The dietary treatment had no effect on the growth performance of chickens or meat yield. The use of extruded linseed or linseed oil only decreased the carcass fatness of the standard chickens but had no effect on the carcass fatness of Label Rouge chickens. The nutritional quality of raw and cured-cooked meat was improved (increased concentration of n-3 FA), whereas the technological quality of the meat (pH, juice loss after cold storage, susceptibility to oxidation, colour, processing yield and shear force value) and sensory quality of the processed products were not or slightly affected. 4. Linked to lower breast yield, to lower lipid content in breast meat and to higher slaughter age, Label Rouge chickens seemed to be less efficient for n-3 FA deposition in breast muscles than standard chickens.

Review: Production factors affecting poultry carcass and meat quality attributes.

Poultry meat mainly comes from standard production system using high growth rate strains reared under indoor intensive conditions. However, it is possible to find also different alternative systems using outdoor extensive rearing conditions and slow-growing lines. These different production systems can affect carcass and meat quality. In this review, quality has been broken down into six properties: commercial, organoleptic, nutritional, technological, sanitary and image, the latter covering the ethical, cultural and environmental dimensions associated with the way the meat is produced, as well as its origin and being particularly valued in many quality labels. The quality of meat is built and can deteriorate along the continuum from the conception of the animal to the fork. Our review details the different factors implicated in the determinism of poultry meat properties and pinpoints critical periods, such as the preslaughter and slaughter periods, and key factors, such as the feeding regimen, via its direct effect on the fatty acid profile, the antioxidant and volatile compound contents, and indirect effects mediated via the growth rate of the bird. Our review also highlights potential antagonisms between different dimensions of quality. The genetic selection for breast meat yield, for example, has been effective in producing carcasses with higher meat yield, but resulting since a decade in the increased occurrence of quality defects and myopathies (white striping, wooden breast, spaghetti meat and deep pectoral disease). Outdoor access has positive effects on the image and nutritional properties (through its effect on the fatty acid profile of meat lipids), but it increases the exposition risk to environmental contaminants and pathologies (parasites, virus, bacteria); it also increases the variability in meat quality linked to the variability of animal performance and slaughter age. The orientation towards more agro-ecological low-input farming systems may present benefits for the image and nutritional properties, but also risks for the commercial (low carcass weight and low breast yield, irregularity in supply), organoleptic (stronger flavour, less tender and darker colour of the meat) and in terms of variability of the different properties that constitute quality. Efforts should be made in the future to better take into account the various dimensions of quality, in consumer information, payment to farmers and genetic selection.

Review: Implication of redox imbalance in animal health and performance at critical periods, insights from different farm species.

The process of oxidative stress occurs all over the production chain of animals and food products. This review summarises insights obtained in different farm species (pigs, ruminants, poultry, and fishes) to underpin the most critical periods for the venue of oxidative stress, namely birth/hatching and weaning/start-feeding phase. Common responses between species are also unravelled in periods of high physiological demands when animals are facing dietary deficiencies in specific nutrients, suggesting that nutritional recommendations must consider the modulation of responses to oxidative stress for optimising production performance and quality of food products. These conditions concern challenges such as heat stress, social stress, and inflammation. The magnitude of the responses is partly dependent on the prior experience of the animals before the challenge, reinforcing the importance of nutrition and other management practices during early periods to promote the development of antioxidant reserves in the animal. When these practices also improved the performance and health of the animal, this further confirms the central role played by oxidative stress in physiologically and environmentally induced perturbations. Difficulties in interpreting responses to oxidative stress arise from the fact that the indicators are only partly shared between studies, and their modulations may also be challenge-specific. A consensus about the best indicators to assess pro-oxidative and antioxidant pathways is of huge demand to propose a synthetic index measurable in a non-invasive way and interpretable along the productive life of the animals.

Review: Quality and authentication of organic animal products in Europe.

The 'organic' label guarantees a production process that avoids the use of synthetic fertilisers, pesticides and hormones and minimises the use of veterinary drugs; however, consumers are demanding guarantees regarding food quality. This article reviews the current state of knowledge on the quality of organic animal products, including the authentication of their organic origin. Quality has been considered as an integrative combination of six core attributes: commercial value, and nutritional, sensory, technological, convenience and safety attributes. The comparison of these attributes between organic and conventional animal products shows high heterogeneity due to variability in farming pratices in both organic and conventional systems. To overcome this, we pinpoint the farming practices underlying the differences observed. This enables light to be shed on the consequences of possible trajectories of organic farming, if specifications are relaxed or tightened up on commitments concerning farming practices that impact product quality. Two recent meta-analyses showed better nutritional attributes in organic milk and meat linked to their higher poly-unsaturated fatty acid (PUFA) content, particularly n-3 PUFAs. Regarding safety, we point to a lack of integrated studies quantifying the balance between positive and negative effects. Organic farming reduces the risk of drug residues and antibiotic resistance, but both outdoor rearing and a frequently longer rearing period increase the animals' exposition to environmental contaminants and the risk of their bioaccumulation in milk, eggs, meat and fish flesh. We highlight antagonisms between quality attributes for certain animal products (lamb, pork). In general, attributes are more variable for organic products, which can be explained by lower genetic selection (poultry), lower inputs and/or greater variability in farming conditions. However, the literature does not address the implications of this greater variability for the consumers' acceptability and the necessary adaptation of manufacturing processes. Further research is needed to document the impacts on human nutritional biomarkers and health. Methods used to authenticate organic origin are based on differences in animal diet composition between organic and conventional systems, but their reliability is hampered by the variability in farming practices.

Liver gene expression in relation to hepatic steatosis and lipid secretion in two duck species.

The susceptibility to development of hepatic steatosis is known to differ between Muscovy and Pekin ducks. Although some experiments were conducted to decipher these differences, few data have been produced to analyse the role of specific genes in this process. For this purpose, expression levels of genes involved in lipid (ATP citrate lyase, malic enzyme 1, fatty acid synthase, stearoyl-CoA desaturase 1, diacylglycerol O-acyl transferase 2, microsomal triglyceride transfer protein, apolipoprotein A1, apolipoprotein B, sterol regulatory element binding factor 1, hepatocyte nuclear factor 4, choline/ethanolamine phosphotransferase 1, carnitine palmitoyl transferase 1A, peroxisome proliferator-activated receptor alpha and sterol O-acyltransferase) and carbohydrate (activating transcription factor 4 or cAMP-response element binding protein, mitochondrial malate dehydrogenase 2 and carbohydrate responsive element binding protein) metabolism and in other functions were analysed in the liver of Pekin and Muscovy ducks fed ad libitum or overfed. A specific positive effect of feeding was observed on the expression of genes involved mainly in fatty acids and TG synthesis and glycolysis, and negative effect on genes involved in beta-oxidation. Interestingly, a strong species effect was also observed on stearoyl-CoA desaturase 1 and to a lesser extent on diacylglycerol O-acyl transferase 2 expression, leading to large differences in expression levels between Pekin and Muscovy overfed ducks, which could explain the difference in lipid metabolism and steatosis ability observed between the two duck species. These results should shed light on gene expression that might underlie susceptibility to hepatic steatosis in humans.

Is there a relationship between the kinetics of lipoprotein lipase activity after a meal and the susceptibility to hepatic steatosis development in ducks?

The difference in the ability of Pekin and Muscovy ducks to develop hepatic steatosis could result from a different peripheral lipoprotein lipase (LPL) activity, which hydrolyses triacylglycerol secreted by the liver. We studied the kinetics of plasma LPL activity in response to a meal at different ages in Pekin and Muscovy ducks. For that purpose, blood samples were taken at 5, 9, 12, 13, and 14 wk of age just before and 1, 2, 4, and 8 h after a meal. To release LPL into general circulation, an i.v. injection of heparin (400 IU/kg of BW) was administered 10 min before blood collection. For that reason, different ducks per genotype were used for each point of measurement (n = 6). Plasma LPL activity measured before the meal was negatively correlated with the weight of the fatty liver measured in the same ducks at 14 wk of age (r = -0.58, P < 0.001). Plasma triacylglycerol level measured before the meal was negatively correlated with plasma LPL activity measured in the same ducks (r = -0.31, P = 0.025) and was negatively correlated with plasma LPL activity measured in the same ducks for each age and each timing (r = -0.39, P < 0.001). At 14 wk of age for Muscovy and Pekin ducks, we observed that a high plasma LPL activity (>200 IU/L of plasma) corresponded to a relatively low development of fatty liver (190 g) induced by overfeeding, whereas a low plasma LPL activity (<150 IU/L of plasma) corresponded to a high propensity to develop fatty liver (470 g). In conclusion, plasma LPL activity measured just before the meal during the rearing period could be used as a marker of hepatic steatosis development during the overfeeding period.

Effect of sex and genotype on carcase composition and nutritional characteristics of chicken meat.

1. The aim of this study was to examine the effect of sex and genotype on carcase composition and nutritional and sensory characteristics of chicken meat. The "Geline de Touraine" (GT) characterised by high carcase fatness was compared with an experimental crossbreed (EC) and "Label rouge" (LR) genotype. 2. Females compared with males, and GT chickens compared with LR and EC chickens were characterised by increased carcase fatness and an increased lipid level in thigh meat. 3. In both breast and thigh meat, the percentage of monounsaturated fatty acids was increased and the percentage of polyunsaturated fatty acids was decreased. However, these effects did not affect sensory characteristics of meat particularly those of roasted breast fillets containing very low lipid level by comparison with thigh meat. 4. Finally, in our study, high carcase fatness was related to high intermuscular fatness affecting the nutritional characteristics of meat but not its sensory attributes.

Ultrasound validity in the measurement of knee cartilage thickness.

OBJECTIVE: To assess the multiexaminer reproducibility and the accuracy comparing with cadaver anatomic specimens of ultrasound (US) measurement of femoral articular cartilage (FAC) thickness. METHODS: In 8 flexed cadaver knees, FAC thickness was blindly, independently and consecutively measured twice by 10 rheumatologists at the lateral condyle (LC), medial condyle (MC) and intercondylar notch (IN) with US. After the US measurements, the knees were dissected. Articular cartilage integrity was evaluated macroscopically in the femoral condyles. FAC thickness was blindly measured in the specimens using a stereoscopic magnifying loupe and a digitised image software. Interexaminer and intraexaminer reliability of US FAC thickness measurement and agreement between US and anatomic measurements were assessed by estimating the intraclass correlation coefficient (ICC). RESULTS: Interexaminer ICCs were higher than 0.90 for MC (p<0.001) and IN (p<0.001) and higher than 0.75 for LC (p<0.01). Mean intraexaminer ICCs were 0.832 for MC (p<0.001), 0.696 for LC (p<0.001) and, 0.701 for IN (p<0.001). Agreement between US and anatomic FAC thickness measurements was good for MC (ICC 0.719; p = 0.020) and poor for LC (p = 0.285) and IN (p = 0.332). Bland-Altman analysis showed that the difference between US and anatomic values was considerably high in the one knee with severely damaged FAC. After eliminating this knee from the analysis, ICCs were 0.883 (p<0.001) for MC, 0.795 (p = 0.016) for LC and 0.732 for IN (p = 0.071). CONCLUSION: US demonstrated a good reproducibility in FAC thickness measurement by multiple examiners. In addition, US FAC thickness measurement was accurate in normal to moderately damaged cartilage.

Correlation between arthroscopic and histopathological grading systems of articular cartilage lesions in knee osteoarthritis.

PURPOSE: Arthroscopic and particularly histopathological assessments have been used to evaluate alterations of knee cartilage in osteoarthritis (OA). The aim of this study was to examine the correlation between an arthroscopic method to grade the severity of chondropathies and the histological/histochemical grading system (HHGS) applied to the corresponding articular cartilage areas in knee OA. METHODS: The articular cartilage surface was examined by chondroscopy using the Beguin and Locker severity criteria, analysing the lesions in 72 chondroscopic areas. Afterwards, samples were obtained by dividing the cartilage surface of the medial tibiofemoral compartment of three OA knee joints into equal squares and they were evaluated histologically using the HHGS. The correlation between both grading methods was assessed using the weighted Kappa coefficient (K(w)). RESULTS: The results obtained with both scores showed good agreement (K(w): mean+/-standard deviation, 0.619+/-0.071). While the average HHGS scores of the chondral samples showed a better agreement with arthroscopic grades 0, I and II, the arthroscopic evaluation has a tendency to overestimate chondral lesions for histological grades III and IV. The intra- and inter-observer reliability of the HHGS evaluation of chondral lesions was excellent (Intraclass Correlation Coefficient: 0.909 and 0.941, respectively). CONCLUSION: In this study, we found a good quantitative correlation between established arthroscopic severity and histopathological scoring systems, particularly in less advanced lesions. Our results suggest that the arthroscopic method is a valuable tool in clinical research to score chondropathies in the medial femorotibial compartment of the OA knee, although some limitations should not be overlooked.

Evolutional patterns of articular cartilage following growth plate injury in rats.

BACKGROUND: No study to date has analyzed the damage of the articular cartilage and its relation to growth plate injury. The purpose of this study was to test whether primary injury to the growth plate contributes to secondary damage to the articular cartilage in rats. METHODS: A total of 109 two-week-old male Wistar rats were allocated to four lesional groups. In group I (controls) no surgery took place. In the remaining animals, an injury was caused in the proximal physis of the left tibia: group II, perichondrial ring injury; group III, direct injury to the growth plate; group IV, traumatic separation of the epiphysis where a Salter-Harris II-type injury was created. The results were assessed at 1 week, 6 weeks, and 6 months. A growth plate score was used. The stereological and histological changes in the articular cartilage were analyzed, and the results were subjected to statistical analysis. RESULTS: Histological studies showed discrete degenerative changes in the articular cartilage in the injured growth plate. Changes in the cell density, mean cell volume, and articular cartilage occurred in the injured growth plate. The changes appeared to be transient in groups II and III. CONCLUSIONS: Primary injury to the growth plate contributes to secondary damage to the articular cartilage in young rats. Our data -- extrapolated to the clinical view -- suggests that a Salter-Harris type II injury does not seem to have impunity to subsequent joint degeneration.

Gene expression and protein content in relation to intramuscular fat content in Muscovy and Pekin ducks.

Independent of their nutritional condition, Pekin ducks always exhibit higher i.m. fat content than Muscovy ducks. To understand this difference between species, the expression level of genes involved in lipid metabolism was analyzed in the pectoralis major muscle of Pekin and Muscovy ducks ad libitum-fed or overfed. The lipoprotein lipase (LPL) gene expression was not different between species and not influenced by overfeeding. The protein content for LPL was higher in Pekin ducks than in Muscovy ducks when birds were ad libitum-fed, whereas in overfed ducks, we found no difference between species. Adipocyte fatty acid-binding protein (A-FABP) gene expression and protein content were higher in Pekin ducks than in Muscovy ducks for each nutritional condition (suggesting a higher intracellular transport within i.m. adipocytes of fatty acids mainly provided by liver for this species). Overfeeding did not affect the expression of genes involved in oxidation [carnitine palmitoyl transferase 1A (CPT1A), cytochrome-c oxidase 4 (COX4), succinyl-coenzyme A:3-ketoacid coenzyme A transferase (SCOT)] but increased the expression of fatty acid synthase (FAS) involved in lipogenesis. For all nutritional conditions, Pekin duck exhibited higher expression levels of CPT1A, COX4, SCOT, and FAS than Muscovy ducks. Results for mRNA SCOT suggested that the muscles of Pekin ducks use ketone bodies as an energy source. In conclusion, i.m. lipogenesis could contribute to the i.m. fat, particularly in Pekin ducks.

Adipogenic genes expression in relation to hepatic steatosis in the liver of two duck species.

Some studies have shown that expression of peroxisome proliferator-activated receptor gamma (PPARG), a key regulator of adipogenesis, and of some adipocyte-specific genes or adipokines are expressed in hepatic steatosis, leading to the concept of 'adipogenic hepatic steatosis' or 'hepatic adiposis.' Most of these studies were conducted in genetic obese mouse models or after manipulation of gene expression. The relevance of this concept to other species and more physiological models was here addressed in ducks which are able to develop hepatic steatosis after overfeeding. The expression of PPARG and other adipocyte-specific genes was thus analyzed in the liver of ducks fed ad libitum or overfed and compared with those observed in adipose tissues. Pekin (Anas platyrhynchos) and Muscovy ducks (Cairina moschata) were analyzed, as metabolic responses to overfeeding differ according to these two species, Muscovy ducks having a greater ability to synthesize and store lipids in the liver than Pekin ducks. Our results indicate that adipocyte-specific genes are expressed in the liver of ducks, PPARG and fatty acid-binding protein 4 being upregulated and adiponectin and leptin receptor downregulated by overfeeding. However, these expression levels are much lower than those observed in adipose tissue suggesting that fatty liver cells are not transformed to adipocytes, although some hepato-specific functions are decreased in fatty liver when compared with normal liver.

Omega-3 polyunsaturated fatty acids provided during embryonic development improve the growth performance and welfare of Muscovy ducks (Cairina moschata).

The welfare of ducks can be affected by unwanted behaviors such as excessive reactivity and feather pecking. Providing long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) during gestation and early life has been shown to improve the brain development and function of human and rodent offspring. The aim of this study was to test whether the pecking behavior of Muscovy ducks during rearing could be reduced by providing LC n-3 PUFA during embryonic and/or post-hatching development of ducklings. Enrichment of eggs, and consequently embryos, with LC n-3 PUFA was achieved by feeding female ducks (n-3F) a diet containing docosahexaenoic (DHA) and linolenic acids (microalgae and linseed oil). A control group of female ducks (CF) was fed a diet containing linoleic acid (soybean oil). Offspring from both groups were fed starter and grower diets enriched with DHA and linolenic acid or only linoleic acid, resulting in four treatment groups with 48 ducklings in each. Several behavioral tests were performed between 1 and 3 weeks of age to analyze the adaptation ability of ducklings. The growth performance, time budget, social interactions, feather growth, and pecking behavior of ducklings were recorded regularly during the rearing period. No significant interaction between maternal and duckling feeding was found. Ducklings from n-3F ducks had a higher body weight at day 0, 28, and 56, a lower feed conversion ratio during the growth period, and lower reactivity to stress than ducklings from CF ducks. Ducklings from n-3F ducks also exhibited a significantly reduced feather pecking frequency at 49 and 56 days of age and for the whole rearing period. Moreover, consumption of diets enriched with n-3 PUFA during the starter and grower post-hatching periods significantly improved the tibia mineralization of ducklings and the fatty acid composition of thigh muscles at 84 days of age by increasing the n-3 FA content.

Effects of intramuscular fat levels on sensory characteristics of duck breast meat.

We conducted a study to evaluate the effects of intramuscular fat levels on the sensory characteristics of duck breast meat. Combining duck genotypes (Muscovy, Pekin, and their crossbreed hinny and mule ducks) and feeding levels (overfeeding between 12 and 14 wk of age vs. ad libitum feeding) enabled us to obtain a wide range of lipid levels in breast muscle. The average values were between 2.55 and 6.40 g per 100 g of muscle. Breast muscle from overfed ducks showed higher lipid and lower water levels than breast muscle from ducks fed ad libitum. Muscle from the overfed ducks was also paler in color and exhibited greater yellowness and cooking loss values. Juiciness was judged lower and flavor more pronounced in overfed ducks. Muscovy ducks exhibited higher breast weight and lower lipid levels than the other genotypes. At the other extreme, Pekin ducks exhibited the highest lipid levels and the lowest breast weights; values for these criteria were intermediate in hinny and mule ducks. Breast muscle of Muscovy ducks was paler, less red, and more yellow than that of other genotypes. Breast muscle of Pekin ducks exhibited the lowest values for lightness, yellowness, and energy necessary to shear meat, as well as the highest cooking loss values, and was judged more tender, juicy and less stringy than that of other genotypes. In contrast, scores for breast muscle of Muscovy ducks were the lowest for tenderness, juiciness, and flavor, and the highest for stringiness. Breast muscle of hinny and mule ducks scored the highest values for redness. Hinny ducks also scored the highest values for flavor. Genotype exerted a higher effect on the sensory quality of breast muscle than did feeding levels. Finally, increasing lipid levels in breast muscle increased lightness, yellowness, cooking loss, tenderness, and flavor, with correlation coefficients of 0.49, 0.47, 0.54, 0.43, and 0.28, respectively. However, breast meat color and tenderness were mainly influenced by genotype.