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.

Reducing the CP content in broiler feeds: impact on animal performance, meat quality and nitrogen utilization.

Reducing the dietary CP content is an efficient way to limit nitrogen excretion in broilers but, as reported in the literature, it often reduces performance, probably because of an inadequate provision in amino acids (AA). The aim of this study was to investigate the effect of decreasing the CP content in the diet on animal performance, meat quality and nitrogen utilization in growing-finishing broilers using an optimized dietary AA profile based on the ideal protein concept. Two experiments (1 and 2) were performed using 1-day-old PM3 Ross male broilers (1520 and 912 for experiments 1 and 2, respectively) using the minimum AA:Lys ratios proposed by Mack et al. with modifications for Thr and Arg. The digestible Thr (dThr): dLys ratio was increased from 63% to 68% and the dArg:dLys ratio was decreased from 112% to 108%. In experiment 1, the reduction of dietary CP from 19% to 15% (five treatments) did not alter feed intake or BW, but the feed conversion ratio was increased for the 16% and 15% CP diets (+2.4% and +3.6%, respectively), while in experiment 2 (three treatments: 19%, 17.5% and 16% CP) there was no effect of dietary CP on performance. In both experiments, dietary CP content did not affect breast meat yield. However, abdominal fat content (expressed as a percentage of BW) was increased by the decrease in CP content (up to +0.5 and +0.2 percentage point, in experiments 1 and 2, respectively). In experiment 2, meat quality traits responded to dietary CP content with a higher ultimate pH and lower lightness and drip loss values for the low CP diets. Nitrogen retention efficiency increased when reducing CP content in both experiments (+3.5 points/CP percentage point). The main consequence of this higher efficiency was a decrease in nitrogen excretion (-2.5 g N/kg BW gain) and volatilization (expressed as a percentage of excretion: -5 points/CP percentage point). In conclusion, this study demonstrates that with an adapted AA profile, it is possible to reduce dietary CP content to at least 17% in growing-finishing male broilers, without altering animal performance and meat quality. Such a feeding strategy could therefore help improving the sustainability of broiler production as it is an efficient way to reduce environmental burden associated with nitrogen excretion.

Large-scale investigation of the parameters in response to Eimeria maxima challenge in broilers.

Coccidiosis, a parasitic disease of the intestinal tract caused by members of the genera Eimeria and Isospora, is one of the most common and costly diseases in chicken. The aims of this study were to assess the effect of the challenge and level of variability of measured parameters in chickens during the challenge with Eimeria maxima. Furthermore, this study aimed to investigate which parameters are the most relevant indicators of the health status. Finally, the study also aimed to estimate accuracy of prediction for traits that cannot be measured on large scale (such as intestinal lesion score and fecal oocyst count) using parameters that can easily be measured on all animals. The study was performed in 2 parts: a pilot challenge on 240 animals followed by a large-scale challenge on 2,024 animals. In both experiments, animals were challenged with 50,000 Eimeria maxima oocysts at 16 d of age. In the pilot challenge, all animals were measured for BW gain, plasma coloration, hematocrit, and rectal temperature and, in addition, a subset of 48 animals was measured for oocyst count and the intestinal lesion score. All animals from the second challenge were measured for BW gain, plasma coloration, and hematocrit whereas a subset of 184 animals was measured for intestinal lesion score, fecal oocyst count, blood parameters, and plasma protein content and composition. Most of the parameters measured were significantly affected by the challenge. Lesion scores for duodenum and jejunum (P < 0.001), oocyst count (P < 0.05), plasma coloration for the optical density values between 450 and 490 nm (P < 0.001), albumin (P < 0.001), α1-globulin (P < 0.01), α2-globulin (P < 0.001), α3-globulin (P < 0.01), and ß2-globulin (P < 0.001) were the most strongly affected parameters and expressed the greatest levels of variation. Plasma protein profiles proved to be a new, reliable parameter for measuring response to Eimeria maxima. Prediction of intestinal lesion score and fecal oocyst count using the other parameters measured was not very precise (R2 < 0.7). The study was successfully performed in real raising conditions on a large scale. Finally, we observed a high variability in response to the challenge, suggesting that broilers' response to Eimeria maxima has a strong genetic determinism, which may be improved by genetic selection.

Partition of metabolizable energy, and prediction of growth performance and lipid deposition in broiler chickens.

The study presented here consisted of the calculation of cross relationships between growth performance parameters, body growth composition, and feed characteristics, using data from an experiment reported in 2 previous publications. In the previous experiment, 30 pelleted diets were given to broiler chickens (8/diet) (21 to 35 d) for in vivo measurement and prediction of AMEn and net energy (NE) values of diets, using 3 trials with 10 diets/trial. In the course of NE determination, individual values for growth, feed intake, and deposition of lipid and protein were measured. Average energy deposited as lipid and protein represented 25.4 and 19.1% AME intake, respectively. Using a multiple regression predicting AME intake, the partial efficiencies of AME for energy deposition as lipid and protein were calculated to be 91.6 and 67.3%, respectively, and the daily amount of AME required for maintenance was evaluated at 0.683 MJ/kg BW0.7. The mean diet NE/AMEn ratios were predicted by an equation combining the lipid content of body growth (positive coefficient) and the apparent digestible protein (ADP) to AMEn ratio (ADP/AMEn), with a quadratic expression for the latter variable. This quadratic response expressed a positive asymptotic relationship, with a plateau for ADP/AMEn values above 1.45 [%/(MJ/kg)]. The equations predicting growth always included either the dietary percentage of water-insoluble cell wall or the AMEn value. The other major parameters predicting growth were either the lipid content of body growth or the CP/AMEn ratio. In many cases, quadratic responses were observed in growth prediction equations. Regressions predicting feed efficiency showed only linear responses. Feed efficiency was predicted precisely by multiple linear regressions based only on AMEn and a dietary protein parameter. According to these regressions, 1% CP was equivalent to 0.247 MJ/kg AMEn in terms of feed efficiency. The most efficient regression predicting the individual lipid content of body growth combined the protein efficiency value (negative coefficient), the CP/AMEn ratio (negative coefficient), AMEn (positive coefficient), and the feather content of body growth (positive coefficient).

Plant and soil intake by organic broilers reared in tree- or grass-covered plots as determined by means of n-alkanes and of acid-insoluble ash.

Free-range birds such as organic broilers may ingest soil and plants during exploration. The estimation of such intakes is of great interest to quantify possible nutritional supplies and also to evaluate the risk of exposure to parasites or to environmental contaminants. Marker-based techniques are now available and would allow to quantify plant and, especially, soil intake in free-range birds, and this quantification was the aim of this study. Methodologically, the proportion of plants in diet intake was determined first using a method based on n-alkanes. Subsequently, the fraction of soil in the total intake was estimated with a second marker, acid-insoluble ash. This approach was carried out to estimate ingested amounts of plants and soil for five successive flocks of organic broilers, exploring grass-covered yards or those under trees, at two time points for each yard: 51 and 64 days of age. Each factor combination (yard type×period=flock number×age) was repeated on two different yards of 750 broilers each. The birds' plant intake varied widely, especially on grass-covered yards. The proportion of plant intake was significantly higher on grass-covered plots than under trees and was also affected, but to a lesser extent, by age or flock number. The ingestion of plants would generally not exceed 11 g of DM daily, except two extreme outliers of nearly 30 g. The daily plant intake under trees tended to be lower and never exceeded 7 g of DM. The amount of ingested plants increased significantly for spring flocks. It increased slightly but significantly with age. The proportion of ingested soil was significantly higher under trees than on grass-covered yards. Dry soil intake was generally low with not more than 3 g per day. Only in adverse conditions - that is, older birds exploring yards under trees in winter - soil intake reached the extreme value of nearly 5 g. Broilers on yards under trees ingested significantly more soil than on grass-covered yards with least square means of, respectively, 2.1 and 1.1 g dry soil per day. These quantifications would allow us to evaluate the impact of plant and soil intake in the management of free-range broilers, especially for the management in organic farming systems. Nevertheless, under the two rearing conditions tested in the current study, the quite low proportions of soil intakes would represent a low risk for the safety of the produced food, unless the birds explore yards on heavily contaminated soil.

Prediction of the net energy value of broiler diets.

Thirty pelleted diets were given to broiler chickens (eight birds per diet; 21 to 35 days of age) for individual in vivo measurements of dietary net energy (NE) value, using three trials with 10 diets/trial. Amino acid formulation of diets was done on the basis of ratios to CP. NE was measured according to the body analysis method. The basal metabolism component of NE values was calculated on the basis of mean metabolic weight using a coefficient obtained in a previous experiment. Information about apparent metabolisable energy (AME) value of diets, AME corrected to zero nitrogen retention (AMEn) and digestibilities of proteins, lipids, starch and sugars was available from a previous publication. In each trial, mean NE/AME ratios of diets varied by about 6%. From the multiple regressions (n=30) expressing NE and AMEn values as functions of digestible component contents, it was deduced that the NE/AMEn ratios assigned to dietary components were 0.760, 0.862, 0.806, 0.690 and 0.602 for CP, lipids, starch, (sucrose+glucose) and fermentable sugars (α-galacto-oligosaccharides and lactose), respectively. The NE/AME ratio of CP was 0.680. Regression calculations showed that the NE values assigned to individual birds (n=240) could also be predicted with diet AMEn values (NE=0.80 AMEn; R 2=0.770) or with an equation combining AMEn value and CP/AMEn ratio (R 2=0.773). The latter ratio was found to be the only additional parameter that was significant when added in the NE regression scheme based on AMEn.

The length of productive life can be modified through selection: an experimental demonstration in the rabbit.

The objective of this study was to assess the feasibility of selecting for functional longevity in rabbits, defined as an ability to delay involuntary culling. Functional longevity was measured as the total number of AI performed after the first kindling. Breeding values were estimated using a discrete survival model. Male parents were selected on the basis of their progeny test results, and the efficiency of selection was estimated in the second generation, as was the correlated response on reproduction traits. A total of 48 males were progeny tested, based on the longevity of 10 daughters bred in 2 different farms. Based on their estimated genetic merit, 5 "high longevity" (HL) and 5 "low longevity" (LL) males were selected divergently and produced a new generation (5 bucks/sires and 10 daughters/bucks). A difference in longevity (+0.75 AI, i.e., 32 d) was observed between the 2 lines. In farm 1, the differences were mainly due to culling (26% in the LL line vs. 14% in the HL line) whereas mortality was similar in the 2 lines. In farm 2, mortality and culling were both higher in the LL line than in the HL line (33 vs. 15% and 19 vs. 7%, respectively). There was no difference between the 2 lines in terms of the reproduction traits recorded for each kindling. Nevertheless, because of the difference in the litter number between the 2 lines, the sum of young rabbits born alive per doe over her lifetime and the sum of young rabbits weaned per doe were higher in the HL line (+5 kits; P < 0.01). Selection for functional longevity using survival analysis is feasible for modifying lifetime reproduction traits.

Prediction of metabolisable energy value of broiler diets and water excretion from dietary chemical analyses.

Thirty various pelleted diets were given to broilers (8/diet) for in vivo measurements of dietary metabolisable energy (ME) value and digestibilities of proteins, lipids, starch and sugars from day 27 to day 31, with ad libitum feeding and total collection of excreta. Water excretion was also measured. Amino acid formulation of diets was done on the basis of ratios to crude proteins. Mean in vivo apparent ME values corrected to zero nitrogen retention (AMEn) were always lower than the AMEn values calculated for adult cockerels using predicting equations from literature based on the chemical analyses of diets. The difference between mean in vivo AMEn values and these calculated AMEn values increased linearly with increasing amount of wheat in diets (P = 0.0001). Mean digestibilities of proteins, lipids and starch were negatively related to wheat introduction (P = 0.0001). The correlations between mean in vivo AMEn values and diet analytical parameters were the highest with fibre-related parameters, such as water-insoluble cell-walls (WICW) (r = -0.91) or Real Applied Viscosity (RAV) (r = -0.77). Thirteen multiple regression equations relating mean in vivo AMEn values to dietary analytical data were calculated, with R² values ranging from 0.859 to 0.966 (P = 0.0001). The highest R² values were obtained when the RAV parameter was included in independent variables. The direct regression equations obtained with available components (proteins, lipids, starch, sucrose and oligosaccharides) and the indirect regression equations obtained with WICW and ash parameters showed similar R² values. Direct or indirect theoretical equations predicting AMEn values were established using the overall mean in vivo digestibility values. The principle of indirect equations was based on the assumption that WICW and ashes act as diluters. Addition of RAV or wheat content in variables improved the accuracy of theoretical equations. Efficiencies of theoretical equations for predicting AMEn values were almost the same as those of multiple regression equations. Water excretion was expressed either as the water content of excreta (EWC), the ratio of water excretion to feed intake (WIR) or the residual value from the regression equation relating water excretion to feed intake (RWE). The best regression predicting EWC was based on sucrose, fermentable sugars (lactose + oligosaccharides) and chloride variables, with positive coefficients. The best equations predicting WIR or RWE contained the sugar and chloride variables, with positive coefficients. Other variables appearing in these equations were AMEn or starch with negative coefficients, WICW, 'cell-wall-retained water', RAV or potassium with positive coefficients.

Effects of a blend of essential oil compounds and benzoic acid on performance of broiler chickens as revealed by a meta-analysis of 4 growth trials in various locations.

A series of growth trials with broiler chicks was conducted in various geographical locations to evaluate the efficacy of a novel eubiotic feed additive (EFA) at various dietary inclusion levels on performance of growing chicks. The EFA product consisted of a blend of essential oil compounds (thymol, eugenol, piperine) with benzoic acid, all belonging to the group of flavoring substances. Although variable in responses, the overall results indicated that 300 mg/kg of this EFA represented an optimum supplementation dose for generation of beneficial performance effects in broilers. A meta-analysis with all data from the 300 mg/kg EFA-supplemented treatments in comparison with the non-supplemented controls revealed that the eubiotic product significantly improved BW on d 21 (+2.0%; P = 0.0021) and on d 42 (+1.4%; P = 0.0151). Furthermore, the birds on the EFA 300 mg/kg treatment expressed a higher average daily gain in the starter phase (d 1-21; +2.1%; P = 0.0023) and over the entire experimental period (d 1-42; +1.5%; P = 0.0154). Feed conversion ratio was more favorable with dietary EFA supplementation (-0.6%; P = 0.0414), when compared with the control birds. Mortality was considered normal and was not affected by the dietary treatment (control = 3.09%; EFA 300 mg/kg = 3.26%). In conclusion, 300 mg/kg of this new eubiotic product demonstrated to effectively improve performance of broiler chicks under various husbandry conditions.

Effects of stocking density on the growth performance and digestive microbiota of broiler chickens.

Increased stocking densities are frequently reported to depress chicken growth performance, but the mechanisms behind this are not fully understood. This study was conducted to investigate the effects of stocking density on growth performance and digestive microbiota, known to be sensitive to environmental factors. Chickens were reared at 2 stocking densities, 12 or 17 birds/m(2). Growth performance was recorded between d 1 and 39, and litter was scored for quality on d 25, 31, and 37. Digestive microbiota was analyzed along the digestive tract (crop, ileum, ceca) of 3- and 6-wk-old chickens by using 2 molecular approaches: a qualitative method (fingerprinting by temporal temperature gradient gel electrophoresis) and a quantitative method (real-time PCR). An increase in stocking density was found to negatively affect the feed conversion ratio (+3.1%) and depress the daily BW gain of broilers (-5.5%) during the period from d 32 to 39 (P ≤ 0.05). Litter quality was reduced with the high stocking density as early as d 25. At 3 wk of age, stocking density strongly affected the fingerprint profiles of the bacterial community, with the highest modifications observed in the crop and ceca (R analysis of similarity = 0.77 and 0.69, respectively, P ≤ 0.05). At 6 wk of age, significant differences in the fingerprint profiles between the stocking densities appeared in the crop and ceca (R analysis of similarity = 0.52 and 0.27, respectively, P ≤ 0.05). The abundance of bacterial groups targeted by real-time PCR was affected by stocking density, but only to a limited extent. Because digestive microbiota may have consequences on the physiology of the digestive tract, its modification by an increase in stocking density may be involved in the reduced growth performance of the bird.

Mutant telomerase RNAs induce DNA damage and apoptosis via the TRF2-ATM pathway in telomerase-overexpressing primary fibroblasts.

Mutant template human telomerase RNAs (MT-hTers) have been shown to induce apoptosis in various cancer cells with high telomerase activity. However, the mechanism by which MT-hTers inhibit the growth of cancer cells and their effects on normal cells remain unknown. To determine the effects of MT-hTers on normal cells, MT-hTer-47A and -AU5 were introduced into IMR90 lung fibroblasts, which have low telomerase levels. Growth of IMR90 cells after MT-hTers infection was not significantly impaired; however, similar treatments in telomerase-overexpressing IMR90 [IMR90 wild-type (WT)hTERT] cells inhibited cell proliferation and induced apoptosis. Confocal microscopy showed that MT-hTers induced DNA damage foci (i.e. 53BP1 and γ-H2AX) in IMR90 WThTERT cells. Microarray analysis revealed that GADD45γ was significantly elevated in MT-hTer-treated IMR90 WThTERT cells. MT-hTers also induced ATM phosphorylation at Ser1981 in IMR90 WThTERT cells, and western blot analysis revealed high levels of phosphorylated p53 after the down-regulation of cellular TRF2 expression in MT-hTer-treated IMR90 WThTERT cells. Taken together, we have shown that MT-hTers induce double-stranded DNA break-like damages in telomerase positive IMR90 WThTERT cells after phosphorylation of ATM and p53 via suppression of TRF2, which may eventually lead to apoptosis via elevation of GADD45γ.

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.

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.

Effects of wheat quality on digestion differ between the D+ and D- chicken lines selected for divergent digestion capacity.

The aim of the experiment was to study the effects of 2 wheat cultivars (Baltimor and Scipion) with different hardness values (75 and 5, respectively) on 2 divergent lines (D+ and D-) of broiler chickens selected on the basis of their digestion ability assessed by AME(n). Wheat was incorporated at 54.6% in diets. The other main ingredients were soybean meal (35.3%) and rapeseed oil (5.5%). Diets were given as pellets from 7 to 26 d. The experimental design was a 2 x 2 factorial design testing 2 wheat cultivars (soft or hard) on 2 selected lines of broiler chickens (high AME(n) or low AME(n)). From 7 to 16 d, D+ line showed lower (P < 0.0001) feed intake and feed:gain ratio than the D- line. At 3 wk of age, the D+ chickens resulted in increased digestibility values (P < 0.01) and 9% increased AME(n) value (P < 0.0001) compared with D-. Wheat cultivar effects on feed efficiency and AME(n) differed between lines. In the D+ line, their values were about 6% higher (P < 0.05) with soft than with hard wheat, whereas they did not differ in the D- line. However, wheat cultivar effect on starch digestibility did not differ between lines; soft instead of hard wheat resulted in about 6% improvement (P < 0.0001) in both lines. In the D- line, soft instead of hard wheat tended to reduce lipid and protein digestibilities, which explained why the starch digestibility improvement due to soft wheat was not converted into a significant AME(n) improvement in D birds. Study of digestive organ size revealed that increased proventriculus and gizzard weight (P < 0.05) could be one of the causes for the better digestion capacity of the D+ line. The pancreas was bigger (P < 0.01) in D- than in D+ birds, which probably came from an adaptation to a digestive disorder in D- birds.

Low birth weight is associated with enlarged muscle fiber area and impaired meat tenderness of the longissimus muscle in pigs.

The objective of this study was to determine the relationships between birth-weight-associated modifications in histological or chemical muscle characteristics and meat quality traits in pigs. At 68 d of age, Pietrain x (Large White x Landrace) female littermates were allocated into 2 groups on the basis of low birth weight (LW = 1.05 +/- 0.04 kg; n = 15) or high birth weight (HW = 1.89 +/- 0.02 kg; n = 15). Pigs were reared in individual pens with free access to a standard diet up to slaughter at approximately 112 kg of BW. During the growing-finishing period, LW and HW pigs had a similar daily feed consumption, whereas G:F was lower (P = 0.009) for LW pigs than for HW littermates. At final BW, LW pigs were 12 d older (P < 0.001) than HW littermates. Estimated lean meat content, relative proportions of loin and ham in the carcass, and weights of LM and semitendinosus muscle (SM) were decreased (P < 0.05) in LW pigs compared with HW pigs. Conversely, the LW pigs exhibited a fatter carcass, greater activity levels of fatty acid synthase and malic enzyme in backfat (n = 15 per group), and enlarged subcutaneous adipocytes (n = 8 per group) compared with the HW pigs. Similarly, lipid content was increased by 25% (P = 0.009), and mean adipocyte diameter was 12% greater (P = 0.008) in the SM from LW pigs compared with that from HW pigs, whereas lipid content did not vary in the LM of either group. Mean myofiber cross-sectional areas were 14% greater in the LM (P = 0.045) and the SM (P = 0.062) of LW pigs than of HW pigs. Conversely, the total number of myofibers was less (P = 0.003) in the SM of LW vs. HW pigs. There were no differences between groups for glycolytic potential at slaughter and rate and extent of postmortem pH decline in both muscles, as well as for LM drip losses. A trained sensory test panel judged the roast loin meat to be less tender (P = 0.002) in LW pigs relative to HW pigs. Scores for juiciness, flavor, flouriness, and fibrousness of meat did not differ between groups. Overall, negative but somewhat low correlation coefficients were found between LM tenderness score and ultimate pH (r = -0.36; P = 0.06) and between LM tenderness and mean cross-sectional area of myofibers (r = -0.34; P = 0.07). This study demonstrates a lower tenderness of meat from pigs that had a LW, partly as a result of their enlarged myofibers at market weight.

Effect of finishing mode (pasture- or mixed-diet) on lipid composition, colour stability and lipid oxidation in meat from Charolais cattle.

Effects of pasture- or mixed-diet finishing mode on colour and lipid stability were measured in meat from Charolais steers, heifers and cows of different ages after refrigerated storage. Meats from pasture- and mixed-diet finished cattle have more or less significant differences in lipid composition which will influence the colour and lipid stability. The mixed-diet finished cattle have about the same proportions of saturated and monounsaturated lipids as pasture-diet finished animals; on the contrary, cattle fed on grass have higher proportions of n-3 PUFA, and to a less extent, of n-6. Finishing diet had an important effect on lipid stability, meat from pasture-finished animals showing significantly lower TBA-RS level than meat from mixed-diet finished animals. Effect of diet was also significant on myoglobin content with a higher content of haeminic iron in mixed-diet finished animals. Effect of diet on colour stability was slight with a beneficial effect of pasture finishing mode, significant only in heifers, and after a meat storage of six days in air.

Effect of xylanase and beta-glucanase supplementation of wheat- or wheat- and barley-based diets on the performance of male turkeys.

The efficiency of a mixture of xylanase and beta-glucanase enzymes was evaluated in two separate experiments on growing turkeys offered diets based on wheat or wheat and barley. 2. In the first experiment, the addition of 560 and 2800 IU of xylanase and beta-glucanase, respectively, per kg of diet significantly improved feed efficiency in turkeys fed on wheat- and barley-based diet throughout the entire experiment (42 d). 3. In the second experiment, the enzyme mixture significantly increased N-corrected apparent metabolisable energy (AMEN) by approximately 5%. 4. Furthermore, the combination of xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Feed efficiency was increased by 2.94, 2.47 and 5.91% in diets based on 500 then 540 g of wheat/kg of diet, 394 then 384 g of wheat and 100 then 150 g of barley/kg of diet and 180 g of wheat and 300 then 350 g of barley/kg of diet, respectively. 5. This enzyme mixture decreased in vitro viscosity of wheat, barley and soybean meal, the effect being larger for wheat and barley than for soybean meal. 6. In conclusion, the supplementation of diets based on wheat and barley with xylanase and beta-glucanase significantly improved body weight gain and feed efficiency. Therefore, wheat and barley could be used more efficiently by turkeys in the presence of an appropriate enzyme preparation.

Influence of outdoor rearing and indoor temperature on growth performance, carcass, adipose tissue and muscle traits in pigs, and on the technological and eating quality of dry-cured hams.

The effects of restricted outdoor rearing during winter (W) or summer (S), and the influence of indoor ambient temperature [17 °C (I17) vs. 24 °C (I24), the latter being considered as control] on pig growth performance, carcass, muscular and adipose tissue traits, and technological and eating quality of dry-cured hams were evaluated. I17 pigs exhibited higher, whereas W had similar and S lower growth rates than the controls (P<0.001). Carcass traits were not different between groups, except in lower back fat weights of S and W pigs (P<0.01). Decrease in environmental temperature affected the fatty acid composition of the back fat leading to higher MUFA and lower SFA and PUFA contents (P<0.001) in I17 and W pigs, whereas S pigs exhibited higher PUFA levels (P<0.001) and fat firmness (P<0.01) than the controls. Rearing system did not significantly influence the intramuscular fat content of Semimembranosus (P=0.08), and had no effect on ultimate pH. In the Longissimus lumborum, percentage and relative area of αR fibers increased in W pigs (P<0.05), but citrate synthase activity did not differ between groups. I17 and W hams exhibited higher processing yields of dry-cured hams than controls (P<0.05). Sensory analyses showed that pig rearing conditions influenced the product appearance, the I17 and W hams exhibiting lower homogeneity (P<0.01) and intensity (P<0.05) of colour, and higher marbling scores (P<0.01) than I24 hams, but had no influence on texture or flavour.

Effect of genotype, sex and rearing temperature on carcase and meat quality of guinea fowl.

1. The aim of our study was to analyse the effect of genotype (label and standard), sex and rearing temperature (simulating daily outdoor in the summer or winter) on the carcase and meat quality of guinea fowl. Using 20 animals per treatment, slaughtered at 96 d of age we measured the breast angle and the thickness of the skin on the wing membrane. Carcases were weighed and cut into parts according to a standardised procedure to determine the percentages of abdominal fat, breasts, wings and thighs with shanks. 2. At slaughter, standard guinea fowl were heavier than label guinea fowl and for both genotypes, the females were heavier than the males (+5.6%). The mean value of breast angle was 85 degrees. This value was significantly higher for the standard guinea fowls and for the females of both genotypes compared with males. Thus, female carcases, particularly standard females, were more compact. The skin was thicker for the standard guinea fowls (0.84 mm vs 0.77 mm) which could be due to more subcutaneous fat. 3. Carcase yield was higher for the males (68.7% vs 68.2%). The percentage of abdominal fat was higher for the standard guinea fowls (2.8% vs 2.4%) and for the females of both genotypes compared with males. The label guinea fowls had higher yields of breasts and thighs with shanks. For both lines, the breast and thigh meat of females was judged more tender and less stringy. 4. Low rearing temperature decreased growth performance but had no significant effect on carcase quality.