Assessing quality of raw milk in southern Greece in the aspect of certain benzimidazole residues

Current perspective on veterinary drug and chemical residues in food of animal origin

The marked increase in the demand for animal protein of high quality necessitates protecting animals from infectious diseases. This requires increasing the use of veterinary therapeutics. The overuse and misuse of veterinary products can cause a risk to human health either as short-term or long-term health problems. However, the biggest problem is the emergence of resistant strains of bacteria or parasites. This is in addition to economic losses due to the discarding of polluted milk or condemnation of affected carcasses. This paper discusses three key points: possible sources of drug and chemical residues, human health problems, and the possible method of control and prevention of veterinary drug residues in animal products.

Ovarian activation delays in peripubertal ewe lambs infected with Haemonchus contortus can be avoided by supplementing protein in their diets

BACKGROUND

The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism's development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep's immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs' diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals.

METHODS

We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing.

RESULTS

We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response.

CONCLUSION

Diet's protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders' productivity.

Anthelmintics residues in raw milk. Assessing intake by a children population

Anthelmintics, such as benzimidazoles and probenzimidazoles, are veterinary drugs used against endoparasites in food producing animals. A number of these drugs are considered responsible for embryotoxicity and teratogenicity. The residue levels of Albendazole, Febantel, Fenbendazole, Mebendazole and some of their metabolites (Albendazole sulphoxide, Albendazole sulphone, Fenbendazole sulfone) were assessed in 123 (42 goat, 69 sheep, 12 bovine) raw milk samples collected from all farms throughout Southern Greece. Sample analysis was performed by HPLC with Diode Array Detector. A high percentage (27.6%) of the samples examined was found to be positive for the investigated compounds. In 14 samples (11.4%), the residues' concentration exceeded the established Maximum Residue Limits. Estimated Daily Intakes were calculated for a population of 723 children aged 10-12 years. Data on milk consumption were obtained by personal interview through a 7-day food frequency questionnaire. The maximum Estimated Daily Intakes for the anthelmintic residues, concerning raw milk, did not exceed the current Acceptable Daily Intake.