Lubomir Leng

Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers

Effects of dietary contamination with various levels of deoxynivalenol (DON) and zearalenone (ZEA) were investigated on Ross 308 hybrid broilers of both sexes. After hatching, all chickens were fed an identical control diet for two weeks. Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg · kg−1, while Group 2 received DON and ZEA at 8.2 and 8.3 mg · kg−1, respectively. The diet of the control group contained background levels of mycotoxins. Samples of blood and tissues were collected after two weeks. Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma γ-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and α-tocopherol in plasma were not affected by dietary mycotoxins. Blood phagocytic activity was significantly depressed in Group 1 and 2. These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.

Effects of excessive selenium supplementation to diet contaminated with deoxynivalenol on blood phagocytic activity and antioxidative status of broilers.

This study examined the effects of excessive dietary supplementation with organic selenium on phagocytic activity and antioxidative status of chickens for fattening fed diet contaminated with deoxynivalenol (DON). Sixty chickens of Ross 308 hybrids were at day of hatching divided into four groups with 15 birds in each. The background DON dietary levels in both negative and positive control groups were 0.2 mg/kg. The complete feed for positive control group was supplemented with Se dose 1 mg/kg in the form of Se-yeast. Group 3 was fed diet with DON level 3 mg/kg while diet for group 4 combined DON level 3 mg/kg with a excessive supplement of Se-yeast (Se dose 1 mg/kg). After 6 weeks of dietary intake, six randomly-chosen chickens from each group were sampled. Feeding of contaminated diet resulted in significantly reduced blood phagocytic activity (19.5 ± 1.1% in the negative control vs. 12.8 ± 0.8% in the DON-treated group, p < 0.05). Se-yeast supplemented to the DON contaminated diet prevented suppression of phagocytic activity. Dietary intake of DON at levels 3 mg/kg did not influence the plasma α-tocopherol level while excessive dietary Se dose reduced it in both Se supplemented groups. Neither the birds of DON-treated group nor the birds from group 4 with DON and Se-yeast showed any response in plasma γ-glutamyltransferase (GGT) activity. Subtoxic dietary level of DON significantly increased the activity of glutathione peroxidase (GPx) in the duodenal mucosa, while additional Se supplementation prevented such a response to mycotoxin. On the other hand, both Se supplemented groups showed significantly elevated GPx activities in blood, liver and kidney, (p < 0.05). The results suggest a potential ability of excessive supplementation of organic selenium to prevent the blood phagocytic activity suppression and changes in GPx activity in duodenal tissue induced in broilers by subtoxic dietary levels of DON.

Risks associated with endotoxins in feed additives produced by fermentation

Increasingly, feed additives for livestock, such as amino acids and vitamins, are being produced by Gram-negative bacteria, particularly Escherichia coli. The potential therefore exists for animals, consumers and workers to be exposed to possibly harmful amounts of endotoxin from these products. The aim of this review was to assess the extent of the risk from endotoxins in feed additives and to calculate how such risk can be assessed from the properties of the additive. Livestock are frequently exposed to a relatively high content of endotoxin in the diet: no additional hazard to livestock would be anticipated if the endotoxin concentration of the feed additive falls in the same range as feedstuffs. Consumer exposure will be unaffected by the consumption of food derived from animals receiving endotoxin-containing feed, because the small concentrations of endotoxin absorbed do not accumulate in edible tissues. In contrast, workers processing a dusty additive may be exposed to hazardous amounts of endotoxin even if the endotoxin concentration of the product is low. A calculation method is proposed to compare the potential risk to the worker, based on the dusting potential, the endotoxin concentration and technical guidance of the European Food Safety Authority, with national exposure limits.

Scientific Opinion on the safety of a manganese chelate of hydroxy analogue of methionine (Mintrex®Mn) as feed additive for all species

Tolerance studies in piglets, laying hens and calves for rearing were submitted. In piglets, effects of manganese on hematological and biochemical parameters were observed, irrespective of the manganese source. In laying hens there was sufficient evidence to conclude that zootechnical parameters were unaffected by the manganese supplementation and source at an overdose. In calves for rearing there were no indications to suggest that MintrexMn is less safe compared to manganese sulfate. Taking also into account the already assessed safety of MintrexMn for chickens for fattening, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that MintrexMn is safe for all species up to the maximum total manganese content authorised in feed.

Effects of borneol on blood chemistry changes in chickens.

It is well established that borneol may be alter bone metabolism. The aim of the study was to investigate the effects of feeding diets supplemented with borneol on blood biochemistry of chickens. Forty chicks of a commercial strain ISA Brown were divided into five groups with 8 birds in each and fed diets supplemented with 0%, 0.1%, 0.05% or 0.025% borneol dissolved in sunflower oil from hatching up to week 11. The concentrations of potassium and magnesium were found to be significantly higher in chickens fed the diet supplemented with 0.1% and 0.025% borneol, respectively. The blood plasma levels of total protein and glucose in chickens treated with 0.05% borneol were significantly lowered. Feeding of diets supplemented with borneol significantly increased levels of bilirubin, cholesterol and total lipids in blood plasma compared to the control group supplemented with sunflower oil only. The present study shows that addition of borneol to the diets can influence some parameters of mineral, lipid and protein metabolism in chicken blood plasma.

Safety and efficacy of l‐arginine produced by fermentation using Corynebacterium glutamicum KCCM 10741P for all animal species

Abstract l‐Arginine is considered to be a non‐essential amino acid for most adult mammalian species, but it is classified as essential for birds, fish, possibly reptiles and also for strict carnivores. The product subject of this assessment is l‐arginine produced by fermentation using a non‐genetically modified strain of Corynebacterium glutamicum (KCCM 10741P). It is intended to be used in feed and water for drinking for all animal species and categories. Species identity of the production organism was confirmed and the strain was sensitive to antibiotics at concentrations at or below thresholds specified by EFSA; thus, C. glutamicum KCCM 10741P may be considered safe by the qualified presumption of safety (QPS) approach. No viable cells of C. glutamicum were detected in the final product. The amount of identified material exceeded 99.8%, and no impurities of concern were detected. The use of l‐arginine produced by C. glutamicum KCCM 10741P is safe for target species when supplemented to diets in appropriate amounts, for the consumer and the environment. l‐Arginine produced by C. glutamicum KCCM 10741P is considered corrosive to skin and eyes and therefore poses a risk by inhalation. The additive is an effective source of arginine for all species. For the supplemental l‐arginine to be as efficacious in ruminants as in non‐ruminant species, it requires protection against microbial degradation in the rumen.

Safety and efficacy of l‐arginine produced by fermentation with Escherichia coli NITE BP‐02186 for all animal species

Abstract l‐Arginine is considered as a non‐essential amino acid for most adult mammalian species, but it is classified as essential for birds, fish, possibly reptiles and also for strict carnivores. l‐Arginine produced by fermentation with Escherichia coli NITE BP‐02186, genetically modified to enhance the production of l‐arginine, is intended to be used in feed and water for drinking for all animal species and categories. The product under assessment does not give rise to any safety concern with regard to the genetic modification of the production strain. Its use as a nutritional additive is safe for target species when supplemented to diets in appropriate amounts. The use of l‐arginine as a feed flavouring agent is unlikely to pose any concern. No risks are expected for the consumer from the use of the product under assessment as a feed additive. It is not irritant to skin or eyes, nor a skin sensitiser. Although the presence of endotoxin activity is of no concern, the available exposure and toxicological data indicate that the additive may pose a risk to users by inhalation. The use of this additive in animal nutrition does not pose a risk to the environment. The additive is an effective source of arginine for all species. l‐Arginine is considered efficacious when used as a flavouring compound in animal nutrition.

Assessment of the application for renewal of authorisation of selenomethionine produced by Saccharomyces cerevisiae CNCM I‐3060 (selenised yeast inactivated) for all animal species

Abstract The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the application for renewal of authorisation of organic form of selenium produced by Saccharomyces cerevisiae CNCM I‐3060 (selenised yeast inactivated) (Sel‐Plex®) for all animal species. In 2006, the FEEDAP Panel delivered an opinion on the safety and efficacy of the additive; subsequently it was authorised in the EU. The evidence provided indicates that the additive currently in the market complies with the conditions of authorisation. No new evidence was found that would make the FEEDAP Panel reconsidering its previous conclusions in the safety for target species, consumers and environment. In particular, the Panel confirms that the use of Sel‐Plex® in animal nutrition does not pose a risk to consumers provided that the maximum selenium supplementation of 0.2 mg/kg feed from Sel‐Plex® is not exceeded, yet respecting the maximum total selenium in feed of 0.5 mg/kg. In the context of the current application, the Panel reviewed toxicological studies; based on two repeated‐dose studies on rats and dogs, it is concluded that the toxic potential of Sel‐Plex® is only related to its selenium content. New data on characterisation of the additive and studies on effects on skin and eyes led the Panel reconsider the safety for the user. The Panel concluded that the additive is hazardous upon inhalation and a likely respiratory sensitiser; owing to the high dusting potential, persons handling the additive are at risk by inhalation. It is considered not irritant to the eyes and skin. A recommendation regarding the denomination of the additive under assessment was proposed by the Panel.

Safety and efficacy of vitamin B2 (riboflavin) produced by Ashbya gossypii ■■■■■ for all animal species based on a dossier submitted by BASF SE

Abstract The European Commission asked EFSA for an opinion on the safety for the target animals, consumer, user and the environment and on the efficacy of a riboflavin‐based additive (minimum 80%) produced by a genetically modified strain of Ashbya gossypii (■■■■■). It is intended to be used in feed for all animal species and categories. The additive under assessment does not give rise to safety concerns on the genetic modification of the production strain. The additive contains 80% of riboflavin (vitamin B2) and 20% of spent growth medium. The additive is safe for target animals with a wide margin of safety. The use of riboflavin 80% produced by A. gossypii ■■■■■ in animal nutrition does not represent a safety concern for consumers. The Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) cannot draw a final conclusion on the risk posed for the user by inhalation of riboflavin produced by A. gossypii ■■■■■ and on the potential to be irritant to skin or eyes. The product under assessment is not a skin sensitiser; however, riboflavin is a known photosensitiser. The use of riboflavin produced by A. gossypii ■■■■■ in animal nutrition does not pose a risk to the environment. The additive is regarded as an effective source of riboflavin in covering the animals requirement when administered via feed. The FEEDAP Panel made recommendations on the description of the additive.

Safety and efficacy of hydroxy analogue of methionine and its calcium salt (ADRY+®) for all animal species

Abstract The European Commission asked EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) to deliver a scientific opinion on the safety and efficacy of ADRY+®. ADRY+® consists of hydroxy analogue of methionine (HMTBa) and its calcium salt (HMTBa‐Ca), both precursors of l‐methionine. HMTBa and HMTBa‐Ca are currently authorised for use as a nutritional additives, under the functional group ‘amino acids, their salts and analogues’. ADRY+® is produced by chemical synthesis and it is intended to be used in feed for all animal species and categories. The FEEDAP Panel concluded that ADRY+® is safe for the target animals. The use of the additive in animal nutrition is not expected to result in an accumulation of HMTBa or its metabolites in edible tissues and animal products. Therefore, its use does not raise safety concerns for the consumer. ADRY+® is irritant to eyes and not irritant to the skin. The FEEDAP Panel cannot conclude on the skin sensitisation potential of this additive. The exposure of the users to the additive by inhalation is expected to be low. The use of this product as a feed additive does not represent a risk to the environment. ADRY+® is an effective source of methionine for protein synthesis in non‐ruminant animals and fish, although HMTBa may show a lower bioefficacy than dl‐methionine. In ruminants, HMTBa is more slowly degraded in the rumen than dl‐methionine.