Potential for Sustainable Poultry Production Based on Local Chicken Breeds and Regional Protein Plants
by Tanja Nolte
Date of Examination:2021-10-28
Date of issue:2022-03-22
Advisor:Dr. Ahmad Reza Sharifi
Referee:Dr. Ahmad Reza Sharifi
Referee:Prof. Dr. Jürgen Hummel
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Abstract
English
During the 20th century, poultry production evolved to a highly specific sector with special chicken lines for egg production on the one hand and meat production on the other. While of broilers both sexes can be used for meat production, until now the male chicks of layer lines are killed on the first day of life because of their low growth potential and the associated economic disadvantages. This practice raises strong ethical concerns and will be forbidden in Germany from 2022 on. Research on alternative solutions is going on, e.g., sex determination in the egg, fattening of the male layer chicks and the use of dual-purpose breeds. Dual-purpose breeds are suitable for both, meat and egg production. In former times, many local breeds have been used this way, but today such breeds are mainly kept as a hobby. Since no selection on performance traits is taking place, the laying and fattening ability of local breeds is low compared to specialized commercial lines. Crossbreeding could be a means to increase the performance of local breeds by heterosis and position effects. Moreover, since the mass market is dominated by commercial hybrids, many local breeds are threatened to become extinct and with them potentially precious genetic resources could get lost. Agricultural use could enhance the chances of these breeds to survive, but for that purpose sufficient performance is necessary. In Chapters 2-4 two local chicken breeds, Bresse Gauloise (BG) and Vorwerkhuhn (VH), and the commercial layer line White Rock (WR) will be evaluated regarding their meat and egg production. In addition, crossbreds of the respective genotypes have been tested to investigate the effect of crossbreeding on performance enhancement. The crosses were: Bresse Gauloise male x White Rock female (BWR), Vorwerkhuhn male x Bresse Gauloise female (VBG), Vorwerkhuhn male x White Rock female (VWR). To cover the demand for protein in animal feedstuff, huge amounts of soybeans and its products are imported to Europe from the Americas. Concerns regarding the sustainability of the use of soybeans are growing due to the cultivation practice and the huge amount of genetically modified seeds. Alternatives to imported soybean meal are regional protein plants, as for example faba beans (Vicia faba L.). Unfortunately, faba beans contain antinutritional factors (ANF), for example Vicin and Convicin (VC), that limit their use in animal nutrition. However, breeding activities led to the reduction of ANF in some varieties. In the present study, the feeding of diets with 20% faba beans with either high or reduced VC contents was compared to a standard soybean meal based diet. The aim of the present study was to test a production system based on local chicken breeds and regional faba beans instead of soy. Such a system could contribute to the avoidance of culling day-old male chicks, preservation of poultry genetic resources and enhanced sustainability in feeding, at least in a niche market. Separated by cockerels and hens, feeding experiments have been conducted to investigate the performance levels of the above-mentioned chicken genotypes, the influence of faba bean feeding and interactions between genotypes and diets. Chapter 2 discusses the weight gain, feed intake and valuable parts at slaughtering of the cockerels of the above-mentioned genotypes. Of the purebreds, the meat-type BG achieved the fastest growth and as crossing partner it enhanced the fattening performance of VH and WR. While the BWR and VBG showed similar growth, the VWR reached the target weight of 2 kg approximately two weeks later. Results for carcass yield, breast and leg percentage were similar for all genotypes. The feeding of faba beans had no adverse effects on the fattening performance and health of the cockerels. The laying curves of the hens, egg weights and eggshell quality traits are shown in Chapter 3, further egg quality traits are discussed in Chapter 4. The laying performance of purebred WR was highest (83.7%), but the BWR also achieved a high production level (80.4%) and a mean egg weight of 58 g. The VWR showed a high peak production but a low persistency resulting in a mean laying performance of 71.1%. Although differences existed, the egg quality of all genotypes was comparable to that of commercial chicken. The feeding of vicin-rich faba beans led to a slight decrease in egg weights, but the vicin-poor faba beans showed no impact on the hen’s performance or on egg quality parameters. In Chapters 2 and 3 it was confirmed that the performance and feed efficiency of the local breeds and their crosses is clearly lower than that of specialized commercial lines. Especially the low feed efficiency raises further questions regarding the environmental sustainability of these production system that have to be balanced against the advantage of preserving poultry genetic resources. The use of regionally grown faba beans and other legumes can enhance the sustainability of the poultry production without performance losses. Taking the results of Chapters 2-4 into account, the BWR cross turned out to be the most promising genotype regarding dual-purpose use, because of its comparably high performance in fattening and laying. In addition, the VBG showed an improvement in both categories compared to purebred VH, which is relevant for the conservation and use of local breeds. The crossbreeding of a meat-type with a layer-type breed could be transferred to other local breeds to enhance their performance level from one generation to the next. The feeding of 20% VC-poor faba beans had no negative impact on the parameters measured in the present study, while the VC-rich variety led to lower egg weights. Overall, the study has shown that the use of local chicken breeds or rather crosses thereof in combination with regional protein feed proves to be a possible production system for niche markets.
Keywords: Poultry; Faba bean; Local chicken breeds; Fattening performance; Laying performance; Egg quality; Vicin