Doctoral thesis (Dissertations and theses)
Selenium status in cattle herds in Wallonia and effects of a fattening diet with selenium-enriched cereals on animal performance, on chemical composition and on meat quality in Belgian Blue bulls
Mehdi, Youcef
2015
 

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Mehdi Youcef - Selenium status in cattle herds in Wallonia and effects of a fattening diet with selenium-enriched cereals on animal performance, on chemical composition and on meat quality in Belgian Blue bulls.pdf
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Keywords :
selenium status; selenium enrichment; Belgian Blue bulls; spelt; Barley; Meat
Abstract :
[en] Selenium (Se 34_79) is a trace element of importance to the body. Its importance is related to its anti-oxidative capacity, and its involvement in the synthesis of thyroid hormones and selenoproteins. These selenoproteins and some selenium compounds such as methylselenol are involved in reducing the accumulation of free radicals and in the prevention of myopathies and some cancers. The presence of selenium in the body ensures correct functioning of the immune system. Studies showed that selenium deficiency reduces phagocytic capacity and cell mobility. The presence of selenium in the body also ensures healthy reproduction, in terms of spermatogenesis or in the prevention of mastitis and metritis in cows. There is, subsequently a reduction of negative economic impact of these anomalies in the farms. The recommended daily intake of selenium in animals varies according to species and the animal type from 100 to 300 µg/kg dry matter (DM). Nutritional selenium requirements in cattle are often not met by locally produced feedstuffs, owing to the very small selenium content. This is mainly due to the types of soils naturally poor in selenium, but also to the low selenium accumulating capacity of forages alone with the pedoclimatic conditions (soil pH and precipitations) which limit the selenium bioavailability in the soil. Consequently, the selenium intake in humans is not met. In Belgium, for example, the average daily intake of selenium is estimated to be between 28 and 60 µg, while the recommended amount by the High Council of Health is 60 µg / day for women and 70 µg / day for men. An additional selenium supplement in feedstuffs for beef and dairy cattle may help to maintain the selenium status, improve cattle health and finally to increase the selenium content in meat and milk. Subsequently, this will help to ensure an adequate selenium supply in humans. The aim of this present research was to assess the effects of a dietary selenium supply in fattening Belgian Blue bulls. The strategy consisted in incorporating in the bulls feed cereals produced with selenium-enriched fertilizers. Instead of the usual addition of sodium selenite and selenized yeasts used as selenium supply, the present enrichment technique follows the soil-plant-animal axis. It aimed primarily to ensure an adequate dietary selenium intake in Belgian Blue bulls, with as effects, a bio fortification of meat in selenium. The first part of the present work is a review paper entitled “Selenium in the Environment, Metabolism and Involvement in Body Functions”. It reports key findings on selenium, its physicochemical properties, its production and presence in the environment, its implication into the organism and effects of its deficiencies in humans and animals. This first study is followed by a second review paper entitled “Selenium in cattle”. It focuses on the effects of selenium deficiency and supplementation in the bovine species (bull, cow and calf). It is thus a synthesis of current understanding about on selenium in cattle. The aim was to review the effects of selenium deficiency and selenium supplementation on growth, on reproduction and on the beef products mainly meat and milk. The experimental part of this work began with an epidemiological study on selenium status in cattle herds in Wallonia. The objective of this study was to provide an overview on/of the blood selenium content in/of cattle in Wallonia. The selenium content was evaluated through the measurement of glutathione peroxidase activity in red blood cells. Data were available on 114 heifers and 184 cows (82 dairy cows and 102 beef cows) distributed over 66 farms in Wallonia. Four agricultural regions were involved in this study namely, the Limoneuse region, the Condroz, the Ardennes and the Famenne region. It appeared from the study that 87% of cattle herds in Wallonia presented a marginal or severe deficiency in selenium (<80 µg/L). Only 13% of animals had adequate selenium status (> 81 µg/L). The lowest selenium status was recorded in the Ardennes region. The average selenium contents recorded in the Ardennes were 34 µg / L in heifers, 44 µg / L in dairy cows and 32 µg /L in beef cows. Compared to other agricultural regions, the highest contents of selenium in dairy cows (64 µg /L) and a beef cow (55 µg/L) were recorded respectively in the Limoneuse Region and in Famenne. The selenium content in beef herds was lower compared to dairy herds (35 vs 56 µg / L, p <0.01). The selenium deficiency could be a determining factor in increasing of frequency of mastitis, metritis and myopathies. Selenium deficiency can be prevented either by selenium dietary supplementation and selenium injections in deficient animals. The use of selenized fertilizers and selenium-enriched ingredients or feedstuffs with high selenium content has been shown to help correct deficiencies observed in cattle. Similar effects can be expected all over Belgium and in countries in which selenium deficiencies have been reported. “Meat composition and quality of young growing Belgian Blue bulls offered a fattening diet with selenium enriched cereals” was the second research of the experimental part of the present work. It consisted to feed growing fattening bulls diet in which spelt and barley were enriched in selenium. The selenium enrichment of the two cereals was obtained by a particular culture technique. The cereals were grown with fertilizers containing sodium selenate. An amount of 4 g of selenate was applied per hectare. These cereals were introduced in the experimental feedstuffs used in the feeding of the fattening Belgian Blue bulls. The objective of this trial was to evaluate the effects of the use of these selenium fortified cereals on growth performance, quality and chemical composition of meat. A total of 23 young bulls were used. Twelve bulls received a control diet containing selenium at a rate of 58 µg/kg DM and the 11 others received a diet with selenium at 173 µg/kg DM. The results of this experiment indicated that the selenium enrichment of diet had no significant effect on growth performance. The final live weight gain, average daily gain (ADG) and feed conversion ratio were similar in both groups. Slaughter data were not influenced either by the addition of selenium. Since the carcass weight, yield, shrinkage and the percentage of muscles were similar in both groups. The meat quality measured by the pH drop, by color, by oxidative rancidity and by water loss was not affected by the addition of selenium. Similarly, in terms of chemical composition of meat, dry matter and protein content were not significantly affected. However, significant effects were recorded on the ether extract content (2.1 vs 1.7 % DM, p <0.05) of meat. The selenium content increased significantly in the plasma (31 vs. 66 ng/ml, p <0.001) and in the Longissimus thoracis muscle (177 vs. 477 ng/g DM, p<0.001). A high increase of selenium was also recorded in the organs: liver (474 vs. 1126 ng/g DM), kidneys (4956 vs. 5655 ng/g DM) and testes (2070 vs. 2309 ng/g DM ). The use of selenium-enriched cereals appeared to be a good method of supplementing selenium in fattening bulls. Such a method of supplementation did not alter the physical and chemical qualities of the meat and induced a decrease in the fat content of meat. Furthermore, there were increased contents of selenium in the blood and organs of the bulls. The consumption of meat produced under such conditions would help to provide between 30 and 57% of daily selenium requirements. In our knowledge, this method of supplementing selenium in cattle, in particular in Belgian Blue bulls, and selenium bio-fortification of meat, is original. The application of the technique used in the present work seems to be useful in helping to reduce selenium deficiency in regions and countries in which they are observed. A similar trial with different levels of selenium in the diet should be designed in order to test a "dose" effect on the same parameters as studied in this work. It would also be interesting in future to conduct a comparative study between the type of supplementation developed in this work and an addition of mineral and/or organic selenium in order to evaluate the "type and source of selenium" effects on the studied parameters. Finally, a technical and economical study should be undertaken to assess the cost of these selenium supplementation types.
Disciplines :
Veterinary medicine & animal health
Author, co-author :
Mehdi, Youcef ;  Université de Liège - ULiège > Doct. sc. vété. (Bologne)
Language :
English
Title :
Selenium status in cattle herds in Wallonia and effects of a fattening diet with selenium-enriched cereals on animal performance, on chemical composition and on meat quality in Belgian Blue bulls
Alternative titles :
[fr] Statut en sélénium chez les bovins en Wallonie et effets d’une ration d’engraissement contenant des céréales enrichies en sélénium sur les performances zootechniques, la composition chimique et la qualité de la viande de taurillons Blanc Bleu
Defense date :
2015
Institution :
ULiège - Université de Liège
Degree :
Docteur en Science Vétérinaires
Promotor :
Dufrasne, Isabelle  ;  Université de Liège - ULiège > Fundamental and Applied Research for Animals and Health (FARAH) > FARAH: Productions animales durables
President :
Hamaide, Annick ;  Université de Liège - ULiège > Département d'Enseignement et de Clinique des animaux de Compagnie (DCC) > Dermatologie des animaux de compagnie
Jury member :
Janssens, Geert
Froidmont, Eric
PINCEMAIL, Joël ;  Université de Liège - ULiège > Département des sciences de la santé publique
Scippo, Marie-Louise  ;  Université de Liège - ULiège > Fundamental and Applied Research for Animals and Health (FARAH) > FARAH: Santé publique vétérinaire
Guyot, Hugues  ;  Université de Liège - ULiège > Département d'Enseignement et de Clinique des animaux de Production (DCP) > Gestion de la santé des ruminants
Detilleux, Johann ;  Université de Liège - ULiège > Département de gestion vétérinaire des Ressources Animales (DRA)
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