A Divergent Selection on Breast Meat Ultimate pH, a Key Factor for Chicken Meat Quality, is Associated With Different Circulating Lipid Profiles.

Background: Chicken meat has become a major source of protein for human consumption. However, the quality of the meat is not yet under control, especially since pH values that are too low or too high are often observed. In an attempt to get a better understanding of the genetic and biochemical determinants of the ultimate pH, two genetic lines of broilers were divergently selected for low (pHu-) or high (pHu+) breast meat pHu. In this study, the serum lipidome of 17-day-old broilers from both lines was screened for pHu markers using liquid-chromatography coupled with mass spectrometry (LC-HRMS). Results: A total of 185 lipids belonging to 4 groups (glycerolipids, glycerophospholipids, sterols, sphingolipids) were identified in the sera of 268 broilers from the pHu lines by targeted lipidomics. The glycerolipids, which are involved in energy storage, were in higher concentration in the blood of pHu- birds. The glycerophospholipids (phosphatidylcholines, phosphatidylethanolamines) with long and polyunsaturated acyl chains were more abundant in pHu+ than in pHu- while the lysophosphatidylcholines and lysophosphatidylethanolamines, known to be associated with starch, were observed in higher quantity in the serum of the pHu- line. Finally, the concentration of the sterols and the ceramides, belonging to the sphingolipids class, were higher in the pHu+ and pHu-, respectively. Furthermore, orthogonal partial least-squares analyses highlighted a set of 68 lipids explaining 77% of the differences between the two broilers lines (R2Y = 0.77, Q2 = 0.67). Among these lipids, a subset of 40 predictors of the pHu value was identified with a Root Mean Squared Error of Estimation of 0.18 pH unit (R2Y = 0.69 and Q2 = 0.62). The predictive model of the pHu value was externally validated on 68 birds with a Root Mean Squared Error of Prediction of 0.25 pH unit. Conclusion: The sets of molecules identified will be useful for a better understanding of relationship between serum lipid profile and meat quality, and will contribute to define easily accessible pHu biomarkers on live birds that could be useful in genetic selection.

Profiles of genetic parameters of body weight and feed efficiency in two divergent broiler lines for meat ultimate pH.

BACKGROUND: Selection for feed efficiency is one of the best ways to decrease poultry production costs and environmental impacts. While literature on its genetic determinism is abundant, it is limited to one or a few periodic values over the animals' lifespans. With the development of new phenotyping tools, kinetics of growth and feed intake are now available, providing access to daily data on feed efficiency. In this study, over the course of 6 weeks, we described the kinetics of body weight (BW), average daily weight gain (ADG), feed intake (FI), and daily cumulative feed conversion ratio (DCFCR) using electronic feed stations. We then estimated the genetic parameters of daily data in two fast growing lines of chicken divergently selected for breast meat ultimate pH (heritability and genetic correlations with breast meat yield and pH). RESULTS: Birds from the line selected to have a more acidic meat (pHu-), were more efficient than those selected to have a less acidic meat (pHu+), with a 4.3% higher BW from d7 to d29 and 5.0% better feed efficiency from d12 to slaughter. The line effect for ADG and DCFCR appeared to be significant as early as d5, which is consistent with the early age at which metabolic differences between the two lines appear. Genetic parameters estimated within each line revealed different genetic determinisms of growth and feed efficiency, with a higher impact of maternal effects on BW during the growing phase (d10 to d20) in the pHu+ line and much higher heritability values of DCFCR during the finishing phase (d26-d42) in the pHu- line. CONCLUSION: Genetic profiles of daily performance highlighted the difference between both lines. Their behavior during dietary transitions reinforced the already known impact of these periods in the animals' lives. Based on the profiles of genetic parameters within each line, it seems feasible to identify early criteria for selecting feed efficiency, but they must be defined for each line, as the genetic determinism of these traits is line-dependent.

The kinetics of growth, feed intake, and feed efficiency reveal a good capacity of adaptation of slow and rapid growing broilers to alternative diets.

Poultry production currently relies on the use of soybean as the main protein and energy source. Reducing its proportion in poultry diets and partly replacing it with local feedstuffs would improve sustainability by reducing dependence on importations and the environmental impact of production. In this study, we evaluated the impact of replacing soybean by sunflower meal, fava bean, canola meal, and dried distillers grains with solubles on the performance of rapid and slow growing chickens. Animals were reared in groups and on the floor. Individual BW and feed intake data were collected throughout each animal's life, thanks to an electronic feed station. At 5 wk (for broilers) and 12 wk (for slow growing chickens), the birds were slaughtered to obtain carcass composition and meat quality data. Adaptation to the alternative diet was studied separately for each genotype. Firstly, we performed ANOVA with diet effect on daily data of individual BW, feed intake, and feed conversion ratio. Secondly, the variability of performances within the group was studied by ANOVA with effects of diet, period, and their interaction. Finally, correlations between daily performances and final performances at slaughter were calculated to understand the construction of final phenotypes and to identify early indicators of final performances. The results showed that the animals adapted well to the alternative diet, mean daily and final performances being mostly similar between the 2 diets for both genotypes (<3% on final BW). However, daily observations highlighted the critical importance of periods around dietary transitions by showing impacted performances for both genotypes. For example, feed conversion ratio of Label Rouge-alternative diet was 12 to 14% lower during the 3 d after transitions than during the 3 d before. It underlined the fact that adapting management of the batch to the alternative diet would be necessary. Correlations between daily and final performances showed that the slaughter performances of rapid growing chickens were mostly determined by BW whereas the main criterion was cumulative feed conversion for slow growing chickens. These correlations also suggested that reserves might be modified with the alternative diet, with rapid growing chickens giving rise to more glycogen reserves and less fat reserves.

Multiple Repeated Sprint Ability Test for Badminton Players Involving Four Changes of Direction: Validity and Reliability (Part 1).

Phomsoupha, M, Berger, Q, and Laffaye, G. Multiple repeated sprint ability test for badminton players involving four changes of direction: validity and reliability (part 1). J Strength Cond Res 32(2): 423-431, 2018-The purpose of this study was: (a) to develop a new sport-specific, repeated-sprint ability test involving 4 changes of direction, namely, the multiple repeated sprint ability (MRSAB) test for badminton players; (b) to determine its validity by comparing the results of 5 different skill levels; and (c) to assess the link between the new test and neuromuscular lower limb and physiological variables. For this purpose, 42 participants were separated into 5 groups to perform the MRSAB test at the same time of day, on 2 occasions, separated by at least 48 hours. The MRSAB test consisted of 2 repetitions of 4 movements (4 × 3 m) separated by 30 seconds of passive recovery. This pattern was repeated 10 times. The best time (BT), mean time (MT), and fatigue index (FI) were measured. Heart rate and blood lactate concentration were also recorded to determine the participants' physiological responses to the test. The results show that the MRSAB test is valid, because it differentiates between the 5 skill levels for BT, MT and FI and offers a reliable method (intraclass correlation coefficient = 0.95 for BT and MT) for testing badminton players, with no differences between the sessions (p > 0.05). Moreover, the link between MT and neuromuscular variables, such as jump height in squats and countermovements (r = -0.55 and -0.60, respectively) and with V[Combining Dot Above]O2max (r = -0.92) reveals that this test uses a combination of the anaerobic and aerobic systems; thus, it can be used by trainers either to improve movement ability or increase these physical qualities.