Monensin residues in the production of Minas Frescal cheese: Stability, effects on fermentation, fate and physicochemical characteristics of the cheese

Consumption and Informal Trade of Milk in the North of Antioquia (Colombia)

The excessive and irrational use of antibiotics to control bovine mastitis and the informal trade in milk with antibiotic residues are objects of great interest for public health, due to the problems associated with the consumption of milk with antibiotic residues on human, animal, and environmental health, and antibiotic resistance. The objective of this study was to understand the attitudes of dairy farmers towards the self-consumption of milk on the farm, the use of milk with antibiotic residues, and the formal and informal milk trade that generates risks for public health. Mixed methods: cross-sectional and grounded theory. Convergent triangulation design. The study was carried out in 9 dairy municipalities in the North of Antioquia, where 216 dairy farmers participated in the quantitative component; and 17 milk producers and 9 veterinarians took part in the qualitative component. A dairy farmer characterization survey was conducted, as well as a survey on the use and marketing of milk from cows with udder health problems and/or under antibiotic treatment. Semistructured interviews were conducted on the same subject. The variable "Intention to sell milk in the village when the dairy industry does not buy it due to high BTSCC" is associated with the BTSCC variable. The variable "Type of marketing reported" is associated with the CFU variable. 5 categories: self-consumption of milk, use of milk with antibiotics, informal milk trade, control of the dairy industry, and beliefs about the elimination of antibiotics in milk, were constructed to theorize about udder health and public health. Sociocultural, political, and economic factors affect decision making in dairy farmers regarding the use and marketing of milk from cows with mastitis and antibiotic residues. These attitudes and behaviors have public health implications.

Tetracyclines in pasteurized milk commercialized in São Paulo, Brazil: occurrence and dietary risk assessment based on single and combined exposure with polyether ionophores

Tetracyclines and polyether ionophores are veterinary drugs frequently used in animals reared for food production. Despite the benefits, residues can be harmful for human health if levels are higher than those considered safe. The aim of this study was to evaluate, by LC-MS/MS, tetracyclines residues in pasteurised milk samples marketed in São Paulo state, Brazil and estimate the exposure of the adult/adolescent/children population. Within the eight antibiotics monitored two were detected, tetracycline and 4-epitetracycline, found in 22.5% and 12.5% of the samples, respectively. Since the same samples had been previously tested for polyether ionophore residues, risk assessment based on dietary exposure to tetracyclines when considered individually and in combination with the ionophores was performed. The daily intakes were below the acceptable daily intake (ADI) for tetracycline. Considering the levels of monensin reported in a previous study, the combined exposure with tetracycline and 4-epi-tetracycline also indicated low potential health concerns.

Feedlot diets containing different starch levels and additives change the cecal proteome involved in cattle's energy metabolism and inflammatory response

Diets for feedlot cattle must be a higher energy density, entailing high fermentable carbohydrate content. Feed additives are needed to reduce possible metabolic disorders. This study aimed to analyze the post-rumen effects of different levels of starch (25%, 35%, and 45%) and additives (monensin or a blend of essential oils and exogenous α-amylase) in diets for Nellore feedlot cattle. The cecum tissue proteome was analyzed via two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and then differentially expressed protein spots were identified with liquid chromatography–tandem mass spectrometry (LC–MS/MS). The use of blends of essential oils associated with α-amylase as a feed additive promoted the upregulation of enzymes such as triosephosphate isomerase, phosphoglycerate mutase, alpha-enolase, beta-enolase, fructose-bisphosphate aldolase, pyruvate kinase, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), l-lactate dehydrogenase B, l-lactate dehydrogenase A chain, l-lactate dehydrogenase, and ATP synthase subunit beta, which promote the degradation of carbohydrates in the glycolysis and gluconeogenesis pathways and oxidative phosphorylation, support pyruvate metabolism through the synthesis of lactate from pyruvate, and participate in the electron transport chain, producing ATP from ADP in the presence of a proton gradient across the membrane. The absence of proteins related to inflammation processes (leukocyte elastase inhibitors) in the cecum tissues of animals fed essential oils and amylase may be because feed enzymes can remain active in the intestine and aid in the digestion of nutrients that escape rumen fermentation; conversely, the effect of monensin is more evident in the rumen and less than 10% results in post-ruminal action, corroborating the hypothesis that ionophore antibiotics have a limited effect on the microbiota and intestinal fermentation of ruminants. However, the increase in starch in these diets promoted a downregulation of enzymes linked to carbohydrate degradation, probably caused by damage to the cecum epithelium due to increased responses linked to inflammatory injuries.

Polyether ionophores residues in pasteurized milk marketed in the state of São Paulo, Brazil: Occurrence and exposure assessment

This paper aimed to survey the occurrence of six polyether ionophores (lasalocid, maduramycin, monensin, narasin, salinomycin and semduramycin) in pasteurized milk using a validated method by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). For that, 40 samples of pasteurized milk, from seven brands, collected in six locations (supermarkets, grocery stores and greengrocers) in the metropolitan region of São Paulo and Campinas, São Paulo State, Brazil, were evaluated. Sampling included whole (18), skimmed (8) and semi-skimmed (10) milk as well as lactose-free (4) products. Only monensin antibiotic residues were found in the analyzed samples. This ionophore was confirmed in 45% of the samples and quantified in 32.5% at concentrations ranging from 0.1 to 0.27 μg kg^-1. The positive samples were whole or semi-skimmed milk. Considering the levels of monensin reported in the present study and data on milk consumption in Brazil, an exposure assessment indicated that the intake of this antibiotic does not represent a risk to health.