Dourmad, J.-Y. ; Garcia-Launay, F. ; Méda, B. ; Lessire, M. ; Narcy, A.In : Wouter Hendriks, Martin W.A. Verstegen, László Babinszky, Poultry and pig nutrition. Wageningen (NLD) : Wageningen Academic Publishers 2019. 315-339 Chapitre d'ouvragePièces jointes : Dourmad_2019.pdfDiet formulation has a direct impact on the efficiency of use of nutrient and energy by pigs and poultry and, consequently, it affects nutrient and waste flow at farm level. All the compounds found in the manure, or emitted into the air, originate from the fraction of the diet which is not retained by the animals. The improvement of efficiency of nutrient retention by pigs and poultry is an efficient way to reduce excretion and emission from the animals. Changing the composition of the feed is efficient to modify the chemical properties of excreta in order to reduce the gaseous emissions and the production of odours. Changing the composition if the feed may allow to better adapt the composition of excreta to their future use for biogas production or as fertilisers. Innovations in the development of enzymes and amino acid production have been and are still important levers for the development of low environmental impact feeding strategies for pigs and poultry. The development of feeding strategies for reducing N and P excretion by pigs and poultry requires a good knowledge of nutrient bioavailability in feed ingredients and a precise evaluation of requirements. Phase feeding is required for practical application of improved feeding strategies. It is facilitated by the use of computerised feeding systems with the perspective of precision feeding.

Autophagy (a process of cellular self-eating) is a conserved cellular degradative process that plays important roles in maintaining homeostasis and preventing nutritional, metabolic, and infection-mediated stresses. Surprisingly, little attention has been paid to the role of this cellular function in species of agronomical interest, and the details of how autophagy functions in the development of phenotypes of agricultural interest remain largely unexplored. Here, we first provide a brief description of the main mechanisms involved in autophagy, then review our current knowledge regarding autophagy in species of agronomical interest, with particular attention to physiological functions supporting livestock animal production, and finally assess the potential of translating the acquired knowledge to improve animal development, growth and health in the context of growing social, economic and environmental challenges for agriculture. Abbreviations: AKT: AKT serine/threonine kinase; AMPK: AMP-activated protein kinase; ASC: adipose-derived stem cells; ATG: autophagy-related; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; BVDV: bovine viral diarrhea virus; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CMA: chaperone-mediated autophagy; CTSB: cathepsin B; CTSD: cathepsin D; DAP: Death-Associated Protein; ER: endoplasmic reticulum; GFP: green fluorescent protein; Gln: Glutamine; HSPA8/HSC70: heat shock protein family A (Hsp70) member 8; IF: immunofluorescence; IVP: in vitro produced; LAMP2A: lysosomal associated membrane protein 2A; LMS: lysosomal membrane stability; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MDBK: Madin-Darby bovine kidney; MSC: mesenchymal stem cells; MTOR: mechanistic target of rapamycin kinase; MTORC1: MTOR complex 1; NBR1: NBR1 autophagy cargo receptor; NDV: Newcastle disease virus; NECTIN4: nectin cell adhesion molecule 4; NOD1: nucleotide-binding oligomerization domain 1; OCD: osteochondritis dissecans; OEC: oviduct epithelial cells; OPTN: optineurin; PI3K: phosphoinositide-3-kinase; PPRV: peste des petits ruminants virus; RHDV: rabbit hemorrhagic disease virus; SQSTM1/p62: sequestosome 1; TEM: transmission electron microscopy.

Background: Rainbow trout is a significant fish farming species under temperate climates. Female reproduction traits play an important role in the economy of breeding companies with the sale of fertilized eggs. The objectives of this study are threefold: to estimate the genetic parameters of female reproduction traits, to determine the genetic architecture of these traits by the identification of quantitative trait loci (QTL), and to assess the expected efficiency of a pedigree-based selection (BLUP) or genomic selection for these traits. Results: A pedigreed population of 1343 trout were genotyped for 57,000 SNP markers and phenotyped for seven traits at 2years of age: spawning date, female body weight before and after spawning, the spawn weight and the egg number of the spawn, the egg average weight and average diameter. Genetic parameters were estimated in multi-trait linear animal models. Heritability estimates were moderate, varying from 0.27 to 0.44. The female body weight was not genetically correlated to any of the reproduction traits. Spawn weight showed strong and favourable genetic correlation with the number of eggs in the spawn and individual egg size traits, but the egg number was uncorrelated to the egg size traits. The genome-wide association studies showed that all traits were very polygenic since less than 10% of the genetic variance was explained by the cumulative effects of the QTLs: for any trait, only 2 to 4 QTLs were detected that explained in-between 1 and 3% of the genetic variance. Genomic selection based on a reference population of only one thousand individuals related to candidates would improve the efficiency of BLUP selection from 16 to 37% depending on traits. Conclusions: Our genetic parameter estimates made unlikely the hypothesis that selection for growth could induce any indirect improvement for female reproduction traits. It is thus important to consider direct selection for spawn weight for improving egg production traits in rainbow trout breeding programs. Due to the low proportion of genetic variance explained by the few QTLs detected for each reproduction traits, marker assisted selection cannot be effective. However genomic selection would allow significant gains of accuracy compared to pedigree-based selection.

Grandhaye, J. ; Lecompte, F. ; Staub, C. ; Venturi, E. ; Plotton, I. ; Cailleau-Audouin, E. ; Ganier, P. ; Ramé, C. ; Brière, S. ; Dupont, J. ; Froment, P.Poultry Science, 2019, 98 (9) : 4140-4152. ArticleIn order to determine the body compo-sition of parental broilers during growth from hatch-ing to adulthood (32 wk of age), we evaluated thekinetics of fattening, growth rate, reproduction param-eters, and body composition of the animals by usingnon-invasive tools such as medical imaging (ultrasoundand CT scan) and blood sample analysis. The use ofCT scanner allowed us to monitor the development ofthe body composition (fatness, bone, muscle, ovary, andtestis growth) of these same animals. These analyseswere accompanied by biochemical blood analyses suchas steroids, metabolites, and some adipokines concen-tration. Difference in the body composition betweenmales and females appeared at 16 wk of age. From20 wk of age, shortly before the onset of lay, the fe-males had 1.6-fold more adipose tissues than males(P

Cold stimulations during egg incubation were reported to limit the occurrence of ascites in broilers subjected to cold temperature after 14 d of age. However, data are lacking on the impacts of such strategy in case of cold temperature conditions at start. This study aimed to evaluate the effects of incubation and posthatch cold challenge on performance, breast muscle integrity, and meat processing quality in broiler chickens. Ross 308 eggs were incubated under control temperature (I0, 37.6°C) or subjected to 15°C during 30 min on day 18 and 19 of incubation (I1). Chicks from each group were reared in floor pens either at standard rearing temperature (T0), from 32°C at 0 d to 21°C at 21 d of age, or exposed to colder rearing temperature (T1), from 29°C at 0 to 21°C at 21 d of age. All birds were then kept at 21°C until slaughter (day 40), when body weights (BW), feed conversion ratio (FCR), breast muscle yield, meat processing quality, and the occurrences of meat defects, hock burns, and pododermatitis were recorded. No significant impact of incubation conditions on hatchability was observed. At day 40, BW was more under T1 than under T0 conditions, with T0 females (but not males) presenting more BW after I1 than after I0 conditions. In the whole period, T1 chickens presented lower FCR than T0 chickens and higher breast meat yields at day 40. The occurrence of white striping was more in I1T1 males than in all other groups, except for the I0T1 males. Hock burns were more frequent in I1T1 males than in all females and I0T0 males, whereas the occurrence of pododermatitis was lower in T0 males than in other groups. Despite some positive effects of I1 incubation on growth after starting under low ambient temperature, this study reveals the limits of such strategy concerning chicken health and welfare, demonstrating that early thermal environment is a major component of the quality and sustainability of chicken meat production.

Simple Summary The practice of beak trimming in laying hens limits the negative consequences of injurious pecking, but could be prohibited by future regulations. We addressed in this study the question of how to prevent or minimize injurious pecking and its consequences, especially when beak trimming is not carried out. We found that a combination of different management strategies applied from rearing to laying stages improved to some extent the welfare of non-beak trimmed birds (lower mortality and fear of a novel object, better feather cover up to 61 weeks of age). Fiber supplementation in the feed did not provide any benefit on pecking-related problems. We suggest practical solutions to limit the consequences of injurious pecking where non-beak-trimmed animals are reared in barn system and transferred to furnished cages, while preserving good welfare, health and productivity. Abstract Beak trimming in laying hens limits the negative consequences of injurious pecking, but could be prohibited by future regulations. This study assessed a combination of management strategies during the rearing period (objects, perches, music, human presence) and laying period (scratching mats, objects, feed fiber supplementation) to raise non-beak-trimmed animals. The welfare and laying performances of beak-trimmed (T) and non-beak-trimmed (NT) ISA Brown birds were compared between groups with (E) or without (NE) these strategies, with or without fiber supplementation in the diet during laying period. Fiber supplementation did not provide any benefit on pecking-related problems. In comparison with NT-NE birds, NT-E birds had lower mortality, were less fearful of a novel object, and had a better feather cover, without a negative impact on productivity (same laying rate and egg quality). Although this study showed advantages of beak trimming (T birds had higher body weights, laying rates and lower hen mortality than NT birds), it highlighted related problems (increasing pullet mortality, decreasing early weights and increasing beak defects). This study proposes practical solutions to limit the consequences of injurious pecking in non-beak-trimmed animals.

In trout aquaculture, tight control of water quality is crucial, especially for young life-history stages. This study examined whether chronic exposure to moderate hypoxia during the fry stage affects the rainbow trout’s behavior during later development. One month after yolk-sac resorption, young trout were exposed for 25 days to hypoxia, obtained by decreasing water flow and bubbling nitrogen gas into the tank (Hypoxia group, H: mean O2: 4.85 mg/L; min: 3.83, max: 6.87 mg/L). A control group was maintained in optimal conditions (C: mean O2: 10.41 mg/L; min: 10.12, max: 10.69 mg/L). At 4 days post-hypoxia, basal (resting) whole body cortisol levels were significantly higher in the H group (166.84 ± 20.67 ng/g) as compared to the C group (103.71 ± 8.78 ng/g), but no post-stress differences were evident (values ∼ 175 ng/g). Long-term effects of hypoxia on various behavioural traits were analysed between 3 and 4 months after the return to normoxia and compared to the C group. The exposure of fry to chronic hypoxia did not impact the fish’s behavioural repertoire (activity, stereotypic behaviour, aggression) in their home tanks after re-acclimation to normoxia. Moreover, basal and post-stress plasma cortisol levels, fear-related behaviours (novel-tank test), and risk-taking behaviours (emergence test) did not differ between the C and H groups. However, this early challenge resulted in an enhanced post-hypoxic growth rate in these fish. Our results show that early exposure to moderate hypoxia does not induce any behavioural changes in rainbow trout after several months of return to normoxia.

The main objective of this paper is to answer the following question: are the containment measures imposed by the majority of world governments effective and sufficient to stop the epidemic of COVID-19? Thanks to a mathematical model that we have developed, we have been able to show that containment measures appear to have slowed the growth of the outbreak. Nevertheless these measures remain only effective as long as a very large fraction of the population remains confined. This means that if no further action is taken, a new wave of contamination larger than the former is expected very shortly after the end of containment date. The combined measures of the large scale test of detection of infected individuals and the social distancing were shown to be effective to overcome the outbreak. While taking separately the both latter measures is not sufficient to prevent a second wave.

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This study provides an integrative description of candidate gene expression across tissues involved in calcium (Ca) metabolism during the egg laying cycle, using the well-defined model of Ca supply as fine or coarse particles of calcium carbonate (CaCO3). Plasma and tissue samples were collected from hens at the peak of laying at 0 to 1, 9 to 10, and 18 to 19 h postovulation (PO). After mRNA preparation from the parathyroid gland, medullary bone, liver, kidney, duodenum, and jejunum, gene expressions were quantified using RT-qPCR. The highest levels of parathyroid hormone (PTH) mRNA in the parathyroid gland (P < 0.05), and of the active form of vitamin D3 1.25(OH)2D3 in the plasma (P < 0.01) were observed at 18 to 19 h PO. During this active phase of eggshell formation, bone resorption was attested to high levels of plasma inorganic phosphorus (iP) and the receptor activation of nuclear factor-κB expression in the bone (P < 0.001 and P < 0.05, respectively). At this stage, 5 genes of the transcellular and the paracellular Ca absorption pathways in the intestine (P < 0.05) and the Ca channel transient receptor potential cation channel subfamily V member 5 (P < 0.05), involved in its reabsorption in the kidney, were overexpressed. At 0 to 1 h PO during the subsequent daylight period, 2 candidates of the transcellular and the paracellular Ca pathways (P < 0.05) remained at high levels in the intestine, while calbindin D 28K expression was the highest in the kidney (P < 0.05). As PTH mRNA and 1.25(OH)2D3 were low, bone accretion was likely active at this stage. The phosphaturic hormone fibroblast growth factor 23 (FGF23) was overexpressed at 18 to 19 h PO (P < 0.05) in the bone when plasma iP was high, which suggested a role in the subsequent reduction of P reabsorption in the kidney, as attested to the decreased expression of P cotransporters, leading to iP clearance from the plasma at 0 to 1 h PO (P < 0.05). The low levels of 1.25(OH)2D3 at this stage coincided with increased expression of the 24-hydroxylase gene in the kidney (P < 0.05). In hens fed fine particles of CaCO3, higher plasma levels of 1,25(OH)2D3 and higher expression of several genes involved in bone turnover reflected a stronger challenge to Ca homeostasis. Altogether, these data support the hypothesis that FGF23 could drive vitamin D metabolism in the laying hen, as previously documented in other species and explain the tight link between P and Ca metabolisms.