Project

Genetic and genomic bases of dietary protein efficiency in pigs

Goal: How can protein requirement in pig production be reduced? So far, the protein content of the fattening feed has been adapted to the increased demand of modern pig breeds. However, it has been shown that fattening pigs are currently over-supplied with protein, resulting in a waste of protein and a high environmental impact. About one third of fattening pigs are clearly protein efficient. This indicates a potential for breeding highly protein-efficient animals in Switzerland. This project aims to estimate the potential for breeding and to find genomic markers for protein efficiency.

Date: 1 March 2018

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Claudia Kasper
added 3 research items
Above 65 kg empty BW, protein deposition is greater in pigs fed protein-restricted compared to standard diets. It is unclear whether the greater CP deposition rate in the finisher period results from the restricted CP supply in the grower period. To elucidate this question, a growth performance study (22.1-110.0 kg BW) was performed with 48 Swiss Large White pigs. They were assigned to either treatment C, LPF or LPGF. The grower-finisher diets of treatment C were formulated based on the Swiss feeding recommendations whereas those of treatment LPGF contained 20% lower digestible CP and essential amino acid levels than diets C. Pigs of the LPGF treatment were offered in the grower and finisher period the standard and the low CP diets, respectively. The pigs were reared in 1 large pen, equipped with 6 automatic feeders, which allowed measuring the individual ad-libitum feed intake per visit. The BW was determined weekly and carcass composition at slaughter was determined by dual-X-ray-absorpiometry. Growth performance and dual-X-ray-absorpiometry data were analyzed with a linear mixed model using treatment as fixed and litter, litter size and farrowing series as random effects. Despite total CP intake was 6 and 16% lower (P< 0.05) in the LPGF than the LPF and C groups, respectively, overall ADG among treatments did not differ. In accordance, gain-to-CP-intake ratio was 9 and 20% greater (P< 0.05) in the LPGF than the LPF and C group. The carcass protein content did not differ whereas carcass fat content was 9% greater (P< 0.05) in LPGF than LPF and C pigs. Carcass protein deposition efficiency was 0.5 and 6.7%-units greater (P< 0.05) in LPGF than LPF and C pigs, respectively. In conclusion, lowering the CP supply by 20% in the grower and finisher compared to solely the finisher period or not at all has no detrimental effect on growth performance, markedly improves CP utilization for carcass protein deposition but slightly increases carcass fatness.
The improvement of efficiency traits, such as protein efficiency (PE), digestible energy efficiency (EnE) and lipid gain (LipG), are relevant given their associations with environmental pollution, cost of production, and the quality of meat. However, these traits are difficult to measure and usually require slaughtering of pigs. Efficiency traits are complex, and several factors, such as genetic predisposition, feed composition, but also individual feeding behaviour may contribute to efficiency. The objective of this study was therefore to evaluate the potential of using feeding behaviour traits to predict efficiency traits under dietary protein restriction. A total of 587 Swiss Large White pigs, consisting of 312 females and 275 castrated males, had ad libitum access to feed and water, and were fed a protein-reduced diet (80% of recommended digestible protein and essential amino acids) from 22.5 ± 1.6 to 106.6 ± 4.6 kg BW. Individual feed intake was monitored and carcass composition (lean and fat mass) at slaughter was determined by dual-energy X-ray absorptiometry. The PE and EnE were calculated as the ratio of protein or energy in the carcass (estimated by dual-energy X-ray absorptiometry) to the total protein or energy consumed. Feeding behaviour traits monitored were daily feed intake, feed intake per meal, number of daily meals, duration per meal, feeding rate, and feeder occupation. A partial least square (PLS) regression was used to predict PE, EnE and LipG from feeding behaviour traits, while including farrowing series (for PE only), age at slaughter and BW at slaughter. Accuracy of PLS regression was assessed based on RMSE and R2 for calibration and validation sets, and on concordance correlation coefficient, which were estimated over 100 replicates of calibration and validation sets. Models with a number of latent variables of 5, 2 and 3 were identified as optimal for PE, EnE, and LipG, which explained 34.64%, 55.42% and 82.68% of the total variation in PE, EnE, and LipG, respectively. Significant concordance correlation coefficient was found between predicted and observed values for PE (0.50), EnE (0.70), and LipG (0.90). In conclusion, individual feeding behaviour traits can better predict EnE and LipG than for PE under dietary protein restriction when fed ad libitum.
Claudia Kasper
added an update
New preprint out on bioRxiv (DOI: 10.1101/2022.08.18.503754)! Esther Ewaoluwagbemiga's main PhD paper 'Genetic analysis of protein efficiency and its association with performance and meat quality traits under a protein-restricted diet' in collaboration with Giuseppe Bee & Agroscope's Swine Research Group. Protein efficiency (and also phosphorus efficiency) are reasonably heritable (43 and 36 %) and thus can be selected. Pig manure containing unused nitrogen (that's what proteins are made of) and phosphorus pollutes the environment. Also, efficient pigs need less nutrients in the feed, which requires less imports. We conclude that protein efficiency is particularly interesting for sustainable production, since there is almost no trade-off with commonly selected production and meat-quality traits. For phenotyping, we used a pipeline developed in-house Agroscope, with which we can precisely monitor protein/phosphorus input and the amount of this nutrient in the pig carcass. First, the feed is formulated and produced in our mill. With RFID in the pig's ear, its entire feed consumption is recorded. After slaughter, half of the carcass is X-ray-scanned, and some simple magic - we know how much nitrogen or phosphorus the pig carcass contains. From this we know the efficiency for the particular nutrient! (see our paper in Animal DOI: 10.1016/j.animal.2021.100307) Apart from protein and phosphorus efficiency. we investigated 12 other traits (production, carcass and meat quality). In total there were > 1,000 pigs, but since the X-ray phenotyping is non-destructive, nothing was wasted! Be assured this was a huge undertaking during the last few years! Most of the work was done by Esther, kudos! The project started in March 2019, Esther joined in Sept and saw everything through until the end in June 2021. But, without our amazing #team of piggery and abattoir staff, chemists, physiologists andnutritionists this simply wouldn't have been possible. This was an enormous effort for many people and also meant a lot of flexibility in terms of planning other experiments. It has been a blast and a hell of a ride! Stay tuned for the continuation of Esther's work (and some spin-offs in the pipeline). In the meantime, check out our efforts to improve phenotyping even more (see our paper in Animal DOI: 10.1016/j.animal.2021.100351).
 
Claudia Kasper
added a research item
Background An essential component in the development of a sustainable pig production is the reduction of nitrogen excretion in fattening pigs. Pig feeds typically contain high levels of dietary crude protein, and due to incomplete conversion to muscle tissue, excess nitrogen is excreted, resulting in environmental problems such as nitrate pollution and greenhouse gas emissions. Therefore, improving protein efficiency (PE), i.e. the proportion of dietary protein that remains in the carcass and is thus available for meat production, is desirable. This study aimed to estimate the heritability (h2) of PE and its genetic correlations with phosphorus efficiency, three performance, seven meat quality and two carcass quality traits when pigs were fed a 20% protein-restricted diet, using a total of 1,071 Swiss Large White pigs. To determine PE, the intake of feed with known nutrient content was accurately recorded for each pig and the nitrogen and phosphorus content of the carcass was determined using dual-energy X-ray absorptiometry. Genetic analysis was performed with a Bayesian animal model. Results We found an average PE of 0.39 ± 0.04 and a heritability of 0.43 (0.29, 0.58). PE showed a low genetic correlation with phosphorus efficiency (0.12 [0.04, 0.21]) and moderate genetic correlations with feed conversion ratio (-0.40 [-0.50, -0.30]), average daily gain (-0.34 [-0.41, -0.23]) and average daily feed intake (-0.61 [-0.69, -0.50]). The genetic correlations between PE and meat quality traits were not significantly different from zero except for meat redness (-0.40 [-0.58, -0.09]) and meat yellowness (-0.27 [-0.45, -0.04]). In contrast, feed conversion ratio showed unfavourable genetic correlations with meat colour, drip loss and cooking loss. Conclusions Protein efficiency is heritable and can be considered in breeding to reduce the environmental impact of pig production without influencing meat quality traits, but the potential for coselecting improved phosphorus efficiency is rather small. Selecting nutrient efficiencies might be a more suitable strategy to reduce nitrogen pollution from manure than focusing on FCR because the latter shows genetic antagonism with meat quality in our population.
Claudia Kasper
added an update
Congratulations to Lea Roch for being awarded the Jean-Pierre Miéville prize for her master's thesis on protein efficiency and potentially damaging behaviours of pigs in this project. This prize is awarded for work dedicated to clinical and non-clinical research into animal diseases and their causes, treatment and control with the aim of promoting animal health or animal welfare. Well done Lea!
 
Claudia Kasper
added an update
The new version of the manuscript in which we attempt to predict efficiency using data generated by single-space automatic feeder stations now includes energy efficiency and lipid gain (in addition to protein efficiency). We use partial least square (PLS) regression for the prediction in the new version. https://www.biorxiv.org/content/10.1101/2020.11.13.381103v1
 
Claudia Kasper
added a research item
The improvement of efficiency traits, such as protein efficiency (PE), digestible energy efficiency (EnE) and lipid gain (LipG), are relevant given their associations with environmental pollution, cost of productions, and the quality of meat. However, these traits are difficult traits to measure and usually require slaughtering of pigs. Efficiency traits are complex, and several factors, such as genetic predisposition, feed composition, but also individual feeding behaviour may contribute to efficiency. The objective of this study was therefore to evaluate the potential of using feeding behaviour traits to predict efficiency traits under dietary protein restriction. A total of 587 Swiss Large White pigs, consisting of 312 females and 275 castrated males, had ad libitum access to feed and water, and were fed a protein-reduced diet (80% of recommended digestible protein and essential amino acids) from 22.5 1.6 to 106.6 4.6 kg BW. Individual feed intake was monitored and carcass composition (lean and fat mass) at slaughter was determined by dual-energy X-ray absorptiometry (DXA). The PE and EnE were calculated as the ratio of protein or energy in the carcass (estimated by DXA) to the total protein or energy consumed. Feeding behaviour traits monitored were daily feed intake (DFI; g/day), feed intake per meal (FIM; g/meal), number of daily meals (NDM; meals/day), duration of meal (DUM; min/meal), feeding rate (FR; g/min), and feeder occupation (FO; min/day). A partial least square (PLS) regression was used to predict PE, EnE and LipG from feeding behaviour traits, while including farrowing series (for PE only), age at slaughter and body weight at slaughter. Accuracy of PLS regression was assessed based on RMSE and R2 for calibration and validation sets, and on concordance correlation coefficient (CCC), which were estimated over 100 replicates of calibration and validation sets. Models with a number of latent variables of 5, 2 and 3 were identified as optimal for PE, EnE, and LipG, which explained 34.64%, 55.42% and 82.68% of the total variation in PE, EnE, and LipG, respectively. Significant CCC were found between predicted and observed values for PE (0.50), EnE (0.70), and LipG (0.90). In conclusion, individual feeding behaviour traits can better predict EnE and LipG than for PE under dietary protein restriction when fed ad libitum.
Claudia Kasper
added a research item
Studies in animal science assessing nutrient and energy efficiency or determining nutrient requirements benefit from gathering exact measurements of body composition or body nutrient contents. Those are acquired by standardized dissection or by grinding the body followed by wet chemical analysis, respectively. The two methods do not result in the same type of information, but both are destructive. Harnessing human medical imaging techniques for animal science can enable repeated measurements of individuals over time and reduce the number of individuals required for research. Among imaging techniques, dual-energy X-ray absorptiometry (DXA) is particularly promising. However, the measurements obtained with DXA do not perfectly match dissections or chemical analyses, requiring the adjustment of the DXA via calibration equations. Several calibration regressions have been published, but comparative studies of those regression equations and whether they are applicable to different data sets are pending. Thus, it is currently not clear whether existing regression equations can be directly used to convert DXA measurements into chemical values or whether each individual DXA device will require its own calibration. Our study builds prediction equations that relate body composition to the content of single nutrients in growing entire male pigs (BW range 20–100 kg) as determined by both DXA and chemical analyses, with R² ranging between 0.89 for ash and 0.99 for water and CP. Moreover, we show that the chemical composition of the empty body can be satisfactorily determined by DXA scans of carcasses, with the prediction error ranging between 4.3% for CP and 12.6% for ash. Finally, we compare existing prediction equations for pigs of a similar range of BWs with the equations derived from our DXA measurements and evaluate their fit with our chemical analysis data. We found that existing equations for absolute contents that were built using the same DXA beam technology predicted our data more precisely than equations based on different technologies and percentages of fat and lean mass. This indicates that the creation of generic regression equations that yield reliable estimates of body composition in pigs of different growth stages, sexes and genetic breeds could be achievable in the near future. DXA may be a promising tool for high-throughput phenotyping for genetic studies, because it efficiently measures body composition in a large number and wide array of animals.
Claudia Kasper
added an update
Already on June 1st, Laurine Couteller, who is doing her master's degree at the ESA in Brest, France, began her internship. She will investigate how gene expression changes in function of mastication behaviours in the pig of the large experiment on protein efficiency. Welcome Laurine!
 
Claudia Kasper
added an update
Claudia Kasper
added an update
The revision is now online (https://www.biorxiv.org/content/10.1101/2020.09.15.286153v3). It contains some technical clarifications following reviewers' suggestions. This version includes Figures 2 and 3 now show measured (chemical) vs predicted (using the calibration equations) variables instead of chemical vs DXA variables. The raw data is now presented in Figures S3 and S4, where we now also include regional regressions, which are regressions on each subset of slaughter weight category (i.e. 20, 60 and 100 kg) separately together with the global regressions. The main results and their interpretations remain unchanged.
 
Claudia Kasper
added an update
Esther Ewaoluwagbemiga's first paper is now out as a preprint.
In this article she assessed whether automatically recorded feeding behaviours can serve as proxies for protein efficiency. Turns out they cannot!
 
Claudia Kasper
added a research item
The objective of this study was to explore the potential of using automatically recorded feeding behaviour as a proxy for protein efficiency (PE) by investigating the relationship between feeding behaviour and PE. A total of 402 Swiss Large White pigs were used in this experiment (204 females and 198 castrated males). Pigs were fed ad libitum on a reduced protein diet (80% of standard) from 20kg to 100kg BW. Individual daily feed intake was monitored and carcass composition at slaughter was determined by dual-energy X-ray absorptiometry (DXA). The PE was calculated as the ratio of protein in the carcass (estimated by DXA) to the total protein consumed. Feeding behaviour traits monitored were daily feed intake (DFI; g/day), feed intake per visit (FIV; g/visit), number of daily visits (NDV; visits/day), duration of visits (DUV; min/visit), feeding rate (FR; g/min), and feeder occupation (FO; min/day). Regression analysis was used to estimate the relationship between PE and feeding behaviour, while correcting for the effects of sex, experimental series and age. Weak Pearson’s correlations (−0.25 to 0.12) were found between PE and feeding behaviour traits. Beta (β) estimates from this analysis for feeding behaviours were also very low (0.0093% to 0.087%). An increase in FR (g/min) will increase PE by 0.087% and an increase in DFI (g/day) will decrease PE by 0.0093%. In conclusion, feeding behaviours are not suitable for the identification of protein-efficient pigs, as estimates are negligible. Implications This study suggests that feeding behaviour traits recorded via automatic feeder are not reliable predictors of protein efficiency in Swiss Large White pigs receiving a protein-reduced diet. Despite the large differences in protein efficiency, only negligible changes in a range of feeding behaviours were observed. Hence, feeding behaviours are not suitable proxies for the high-throughput phenotyping of protein efficiency and the selection of live animals for use in nutrition experiments or for breeding.
Claudia Kasper
added an update
Our new group Animal GenoPhenomics is alive! Efficient, robust and healthy livestock.
 
Claudia Kasper
added an update
"Accuracy of predicting chemical body composition of growing pigs using dual-energy X-ray absorptiometry"
 
Claudia Kasper
added 2 research items
Studies in animal science assessing nutrient and energy efficiency or determining nutrient requirements necessitate gathering exact measurements of body composition or body nutrient contents. Wet chemical analysis methods or standardized dissection are commonly applied, but both are destructive. Harnessing human medical imaging techniques for animal science can enable repeated measurements of individuals over time and reduce the number of individuals required for research. Dual-energy X-ray absorptiometry (DXA) is particularly promising due to its low acquisition and operating costs, low levels of radiation emission and simple image processing. However, the measurements obtained with DXA do not perfectly match dissections or chemical analyses, requiring the adjustment of the DXA via calibration equations. In principle, DXA results should be independent of animal size and body composition, because bone mineral content and the content of fat and lean tissue are derived from the attenuation of X-rays transmitted through the body. Several calibration regressions have been published, but comparative studies are pending. Thus, it is currently not clear whether existing regression equations can be directly used to convert DXA measurements into chemical values or whether each individual DXA device will require its own calibration for the animal’s breed, age, class or sex. Our study builds prediction equations that relate body composition to the content of single nutrients in growing entire male pigs (BW range 20–100 kg) as determined by both DXA and chemical analyses, and we present the accuracy of those predictions. Moreover, we show that the chemical composition of the empty body can be satisfactorily determined by DXA scans of carcasses. This opens up promising possibilities for the reduction of invasive procedures in the course of nutritional studies. Finally, we compare existing prediction equations for pigs of a similar range of body weights with the equations derived from our DXA measurements and evaluate their fit with our chemical analyses data. We found that existing equations for absolute contents that were built using the same DXA beam technology predicted our data more precisely than equations based on different technologies and percentages of fat and lean mass. This indicates that the creation of generic regression equations that yield reliable estimates of body composition in pigs of different growth stages, sexes and genetic breeds could be achievable in the near future. DXA may be a promising tool for high-throughput phenotyping for genetic studies, because it efficiently measures body composition in a large number and wide array of animals. Implications The ability to determine body composition non-invasively opens opportunities for improving studies of nutrition, nutrient balance and genetics. The present study contains regression equations to estimate the nutrient composition (energy, water, ash, Ca, P, CP, N and lipid) in the empty body of live pigs and in pig carcasses within a BW range from 20 to 100 kg using DXA. We present regression equations to estimate the EB composition directly from the carcass. This rapid and non-destructive method permits to reduce costs, time and number of animals needed for research, since the same individuals can be scanned repeatedly.
Increasing stress resilience of livestock is important for ethical and profitable meat and dairy production. Susceptibility to stress can entail damaging behaviours, a common problem in pig production. Breeding animals with increased stress resilience is difficult for various reasons. First, studies on neuroendocrine and behavioural stress responses in farm animals are scarce, as it is difficult to record adequate phenotypes under field conditions. Second, damaging behaviours and stress susceptibility are complex traits, and their biology is not yet well understood. Dissecting complex traits into biologically better defined, heritable and easily measurable proxy traits and developing biomarkers will facilitate recording these traits in large numbers. High-throughput molecular technologies (“omics”) study the entirety of molecules and their interactions in a single analysis step. They can help to decipher the contributions of different physiological systems and identify candidate molecules that are representative of different physiological pathways. Here, we provide a general overview of different omics approaches and we give examples of how these techniques could be applied to discover biomarkers. We discuss the genetic dissection of the stress response by different omics techniques and we provide examples and outline potential applications of omics tools to understand and prevent outbreaks of damaging behaviours.
Claudia Kasper
added an update
Lea Roch from the Animal Welfare Division of Vetsuisse Bern will start her project on Monday, Aug. 10. She will investigate whether, under dietary protein restriction, protein efficiency is related to increased tendencies to orally manipulate objects and conspecifics' tails and ears. Welcome Lea!
 
Claudia Kasper
added an update
I am looking for a motivated Postdoc to join me via a Marie Skłodowska-Curie Individual Fellowship. Calls are open at the moment until 09/09/2020 and I would be excited to help develop a proposal for functional genomics in pigs (in conjunction with protein efficiency, but other phenotypes are possible). At Agroscope, we provide an excellent working environment in proximity of Fribourg and Bern in Switzerland, with a wide range of internal and external lab facilities and an excellent experimental pig barn, feed mill and slaughterhouse. Contact me if you are interested in developing your own project with me on whole-genome gene expression, gene regulation, gene co-expression networks in relation to nutritional efficiency (or potentially stress susceptibility, ...) in pigs; briefly, if you want to have a look inside the "pink box"!
 
Claudia Kasper
added an update
Our article "Investigating the potential for genetic improvement of nitrogen and phosphorus efficiency in a Swiss large white pig population using chemical analysis" appeared this week in Journal of Animal Breeding and Genetics (DOI: 10.1111/jbg.12472). The data can be found at Zenodo (https://doi.org/10.5281/zenodo.3368899). The supporting information to this article can be found here on RG.
 
Claudia Kasper
added 2 research items
Pig production contributes to environmental pollution through excretion of phosphorus and nitrogenous compounds. European pig production requires annual imports of currently 36 million tons of soya bean, because domestic plant protein sources often do not meet the required protein quality. Most of the mineral phosphate sources are also imported. It is therefore desirable to improve nutrient deposition efficiency through selective breeding, that is to realise similar growth rates and carcass compositions as currently achieved but with a lower intake of dietary crude protein or phosphate. For a preliminary evaluation of the potential of selecting for increased nutrient deposition efficiency, we estimated genetic parameters for nitrogen and phosphorus efficiencies in a Swiss Large White pig population including 294 individuals. Nutrient efficiency phenotypes were obtained from wet‐chemistry analyses of pigs of various live weights. Heritability of nitrogen efficiency was estimated at 41%. Heritability of phosphorus efficiency was very low (0.3%), but positive genetic correlations with nitrogen efficiency suggest that breeding for nitrogen efficiency would positively affect phosphorus efficiency. Further studies are needed to improve the quality of estimates and to obtain accurate high‐throughput measures of nutrient efficiency to be implemented on farms.
Claudia Kasper
added an update
Poster presentation on March 3, 2020, at the annual meeting of the GfE, the German Society for Nutrition, in Göttingen.
 
Claudia Kasper
added an update
Esther will work on quantitative genetics parameters of protein efficiency. She will also do a GWAS and genomic prediction on the data set that is currently collected.
Welcome Esther!
 
Claudia Kasper
added an update
Genetic parameters of protein efficiency in a Swiss Large White pig population: preliminary results
Pork production contributes to environmental pollution through the emission of nitrogen and phosphorus compounds. In addition, pig fattening in Europe usually requires imports of soybean, since the protein requirement of feed cannot be easily met by domestic plant-protein sources alone. It is therefore desirable to improve protein efficiency, i.e. to achieve a similar protein uptake in the carcass with a lower intake of dietary protein, through selective breeding. For a preliminary evaluation of the potential of breeding for higher nitrogen efficiency in this population, we used the results of previous experiments with protein-reduced feed to estimate genetic parameters of nutrient efficiency in Swiss Large White pigs. Protein efficiency could be determined by using automated feeders with individual pig recognition system allowing for detailed information of individual lifetime consumption. We determined protein contents of the feed and of the body fractions after slaughtering with wet-chemistry analyses. Heritability of protein efficiency in the whole body (including organs and cleaned gastro-intestinal tract) was estimated at 32% and in the carcass (including the head but entrails removed) at 16%. The common environment played a minor role in shaping nitrogen efficiency. Positive phenotypic correlations between the two traits suggest that selection for one trait will lead to an increase in the other trait. However, since protein-efficient pigs took longer to reach the target slaughtering weight, a slight delay in the growth of protein-efficient pigs might be expected. We have just begun a more thorough investigation of nutrient efficiency with studies yielding higher sample sizes to improve the quality of estimates and to conduct genetic correlation analyses with production traits. We further aim at obtaining information on the genes underlying nutrient efficiency in pigs as well as their functions.
 
Claudia Kasper
added 2 research items
L'élevage porcin participe à la pollution de l'environnement par l'émission de com-posés azotés. En outre, l'engraissement des porcs en Suisse nécessite l'importation de grandes quantités de soja, car les besoins en protéines ne peuvent pas être cou-verts par des sources de protéines végétales produites en Suisse. L'amélioration de l'efficience protéique, c'est-à-dire l’obtention par la sélection de la même teneur en protéines dans la carcasse tout en diminuant l’ingestion de matière azotée, est donc souhaitable. Pour l'évaluation préliminaire du potentiel de sélection en vue d’obtenir une meilleure efficience protéique et de l’azote, des paramètres génétiques de ce caractère chez le grand porc blanc suisse ont été estimés sur la base des résultats d’essais effectués avec des aliments à teneur réduite en protéines. L'héritabilité de l'efficience protéique a été estimée à 32 % dans le corps vif vide, soit à 16 % dans la carcasse. Des corrélations phénotypiques positives avec l'efficience du phosphore suggèrent que par une sélection axée sur l'efficience de l'azote, celle-ci pourrait également être augmentée. Toutefois, il faut s'attendre à un léger retard dans la croissance des porcs présentant une haute efficience protéique. D'autres études sont nécessaires pour améliorer la pertinence des estimations et obtenir des infor-mations sur les gènes à la base de l'efficience protéique.
Die Schweinehaltung trägt durch die Emission von Stickstoffverbindungen zur Umweltbelastung bei. Ausserdem benötigt die Schweinemast in der Schweiz den Import von Soja, da der Proteinbedarf nicht durch heimische pflanzliche Protein-quellen gedeckt werden kann. Die Verbesserung der Proteineffizienz, d.h. gleich hoher Proteinansatz im Schlachtkörper bei geringerer Rohproteinaufnahme durch selektive Züchtung, ist daher erstrebenswert. Zur vorläufigen Evaluation des Poten-tials einer Zucht auf höhere Protein- bzw. Stickstoffeffizienz wurden genetische Pa-rameter dieses Merkmales beim Schweizerischen Edelschwein anhand von Unter-suchungsergebnissen mit proteinreduziertem Futter geschätzt. Die Vererbbarkeit (Heritabilität) der Proteineffizienz wurde auf 32 % im Leerkörper bzw. auf 16 % im Schlachtkörper geschätzt. Positive phänotypische Korrelationen mit der Phospho-reffizienz deuten darauf hin, dass durch die Zucht auf Stickstoffeffizienz diese auch erhöht werden könnte. Allerdings ist eventuell eine geringfügige Verzögerung des Wachstums von proteineffizienten Schweinen zu erwarten. Weitere Studien sind nötig, um die Qualität der Schätzungen zu verbessern sowie um Informationen zu den der Proteineffizient Proteineffizienz zugrundeliegenden Genen zu erhalten.
Claudia Kasper
added an update
I offer a PhD position in this project in collaboration with ETH Zurich. Please see the following link for details: https://www.eth-gethired.ch/en/jobs/phd-project-breeding-sustainable-pigs-the-genetic-basis-of-nitrogen-efficiency-43919/show
or contact me for further details
 
Claudia Kasper
added an update
Pigs are fed protein-rich feed during fattening. However, some individuals might be genetically predisposed to convert dietary protein more efficiently. Through breeding, the average dietary protein efficiency can be increased in the population. Ideally, after selection, pigs need less protein-rich feed while maintaining the same growth rate and meat quality. Less soy protein will have to be imported for pig feed, and the amount of nitrogen in the manure will be reduced.
 
Claudia Kasper
added a project goal
How can protein requirement in pig production be reduced? So far, the protein content of the fattening feed has been adapted to the increased demand of modern pig breeds. However, it has been shown that fattening pigs are currently over-supplied with protein, resulting in a waste of protein and a high environmental impact. About one third of fattening pigs are clearly protein efficient. This indicates a potential for breeding highly protein-efficient animals in Switzerland. This project aims to estimate the potential for breeding and to find genomic markers for protein efficiency.