Traumatic Injuries Detected during Post-Mortem Slaughterhouse Inspection as Welfare Indicators in Poultry and Rabbits.

The findings of traumatic injuries during post-mortem inspection in slaughterhouses reflect the level of pre-slaughter handling of animals at the farm and during transport to the slaughterhouse. The prevalence of traumatic injuries was monitored in poultry (1,089,406,687 broiler chickens, 20,030,744 laying hens, 1,181,598 turkeys, 37,690 geese, 28,579,765 ducks) and rabbits (1,876,929) originating from farms in the Czech Republic and slaughtered in slaughterhouses in the Czech Republic between 2010 and 2019. The greatest incidence of traumatic injuries was found in laying hens (2.80%) and rabbits (1.52%); while the overall incidence of trauma was less than 0.5% in other species and categories. The results show that the current rearing conditions and/or pre-slaughter handling of poultry and rabbits particularly affect the limbs; traumatic findings were significantly (p < 0.01) more frequent on the limbs than on the trunk in all species studied. In poultry, traumatic findings on the trunk were orders of magnitude lower to negligible, so the focus should be on preventing injuries to the limbs. In rabbits, the difference was less pronounced, and many injuries were found on both limbs (0.83%) and trunk (0.69%). Our results emphasize the need to reconsider both housing and pre-slaughter handling methods to determine minimum standards for the protection of rabbits, which are still lacking in European legislation.

Effects of waterborne antidepressants on non-target animals living in the aquatic environment: A review.

After application, antidepressants, like other pharmaceuticals, are excreted from human body in their native form or as metabolites and enter the aquatic environment via different pathways. As concentrations of antidepressant residues in water continue to increase, their effects on non-target animals are being discussed. The aim of this study is to summarize current knowledge about the effects of wateborne antidepressants on non-target animals living in surface waters - invertebrates, fish and amphibians. Selective serotonin reuptake inhibitors such as fluoxetine, sertraline, and citalopram have been found to effect behavior, reproduction, and development in both invertebrates and vertebrates. Venlafaxine, belonging to the group of selective serotonin-noradrenalin reuptake inhibitors, not only affected behavior but also showed the potential to reduce survival in fish. Tricylic antidepressants are known to have various side-effects when consumed by humans. Moreover, in fish, exposure resulted in a significant increase in mortality, developmental retardation, morphological anomalies, and pathological changes in brain, heart, and cranial and caudal kidney. In addition, changes in antioxidant enzyme activity as well as increased lipid peroxidation were observed, even at the lowest tested concentrations. According to current knowledge, antidepressants occuring in surface water are able to affect the behavior, reproduction, development, and survival of aquatic invertebrates and vertebrates.

The effects of subchronic exposure to terbuthylazine on early developmental stages of common carp.

The aim of this study was to assess the impact of terbuthylazine in surface waters on fish under experimental conditions. Subchronic toxic effects on embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30-day toxicity test. The exposure to terbuthylazin showed no effect on mortality, but significant differences (P < 0.0001) were revealed on weight and growth parameters at concentrations of 520 and 820 µg/L. The inhibition of specific growth rate at concentrations of 520 and 820 µg/L was 14% compared to the control group. No significant negative effects on total body length and body weight were observed at lower concentrations (0.9 and 160 µg/L). The concentrations 520 and 820 µg/L were associated with a delay in development compared to other experimental groups and controls. On the basis of weight and growth rate evaluation and determination of developmental stages, the No Observed Effect Concentration (NOEC) of terbuthylazine was estimated at 160 µg/L and the Lowest Observed Effect Concentration (LOEC) was 520 µg/L. According to these results, the reported environmental concentration of terbuthylazine in Czech rivers does not impact growth, development, morphology, or histology of carp embryos and larvae.

Effects of subchronic exposure to simazine on zebrafish (Danio rerio).

OBJECTIVES: Simazine is a triazine herbicide which has been used for a long period in agriculture and in the aquatic environment for control of weeds and algae. The aim of this study was to investigate the effects of subchronic exposure to simazine on growth and the development of histopathological changes in selected organs (gills, kidney, liver) in Danio rerio. METHODS: Juvenile growth tests were performed on D. rerio according to the OECD method No. 215. Fish at the age of 20 days were exposed to the environmental simazine concentration commonly detected in Czech rivers (0.06 µg.L-1) and a range of sublethal concentrations of simazine (0.6, 6.0 and 60.0 µg.L-1) for 28 days. RESULTS: There were no significant differences (p<0.05) between the specific growth rates (r) of the test groups and those of both control groups. Histopathological examination revealed pathological changes in fish exposed to a simazine concentration of 60.0 µg.L-1. The values of NOEC and LOEC of simazine were 6.0 µg.L-1 and 60.0 µg.L-1. CONCLUSIONS: The environmental concentration of simazine in Czech rivers did not have any effects on the growth and development of histopathological changes in D. rerio.

Polyaluminium chloride (PAX-18) - acute toxicity and toxicity for early development stages of common carp (Cyprinus carpio).

OBJECTIVES: The aim of this study is to assess the toxicity of PAX-18 in different developmental stages of common carp (Cyprinus carpio). The preparation PAX-18, with its active ingredient polyaluminium chloride (9% of Al), is a coagulation agent that is used mainly to precipitate phosphates, to prevent surface water eutrophication and incidences of cyanobacteria. It is applied to the water environment and thus could present a potential risk to fish. DESIGN: The toxicity tests were performed on common carp according to OECD (203, 210) methodologies. The acute toxic effect was evaluated for juveniles and the early development stage effect was observed in embryo-larval toxicity tests. The results of the toxicity tests (the number of dead individuals at particular test concentrations) were subjected to a probit analysis using an EKO-TOX 5.2 programme to determine the LC50 values of PAX-18. RESULTS: Acute toxicity value expressed as 96hLC50 was 753.1 +/- 24.3 mg.l-1 (67.8 mg.l-1 Al). Effect on early development stage expressed as the no observed effect concentration was 10 mg.l-1 (0.9 mg.l-1 Al), the lowest observed effect concentration was 50 mg.l-1 (4.5 mg.l-1 Al). No significant effects of the preparation PAX-18 in concentrations of 50 mg.l-1 of PAX-18 and lower were found on hatching, length and weight parameters, morphology and histopathology. CONCLUSION: The lethal concentration of PAX-18 found in acute toxicity tests on common carp was 7-14 times higher than the concentration which is usually applied to water (5-10 mg.l-1 Al). Moreover, fish in eutrophicated water sources are exposed to PAX-18 concentrations corresponding with the lowest observed effect concentration only for a short time, therefore the effect on them can be considered as minimal.

Terbutryn toxicity to Danio rerio: effects of subchronic exposure on fish growth.

OBJECTIVES: The aim of this study was to investigate effects of subchronic exposure to sublethal levels of terbutryn on growth and on histopathological changes in Danio rerio. DESIGN: The acute toxicity tests were performed on the juvenile stage of Danio rerio according to OECD No. 203 Fish, Acute Toxicity Test. The juvenile growth tests were performed on D. rerio according to the OECD method No. 215. Fish at the age of 20 days were exposed to the terbutryn environmental concentration commonly detected in the Czech rivers (0.02 microg L-1) and the range of sublethal concentrations of terbutryn (0.06, 0.2, 0.6 and 2 mg L-1) for 28 days. RESULTS: The 96hLC50 terbutryn mean value for the juvenile stage of D. rerio was 5.71 +/- 0.46 mg L-1. A significant decrease (p < 0.01) in the fish growth caused by terbutryn was observed in the concentration of 0.6 mg L-1. The value of NOEC was 0.2 mg L-1 and LOEC was 0.6 mg L-1 of terbutryn. We found the damage to tubular system of kidneys in the concentration of 0.6 mg L-1 of terbutryn. CONCLUSION: The environmental concentration of terbutryn in the Czech rivers did not have any effects on growth and on histopathological changes in D. rerio and this concentration is lower than determined LOEC and NOEC values of terbutryn.

Comparison of the sensitivity of different fish species to medical substances.

OBJECTIVES: Formaldehyde, sodium chloride and potassium permanganate belong to the commonly used substances for fish treatment. The aim is to define and compare their acute toxicity and therapeutic index between two fish species - Danio rerio and Poecilia reticulata. DESIGN: To determine acute toxicity of these compounds, the semistatic method was implemented in compliance with the OECD No. 203 (Fish acute toxicity test). In each test series, 4 acute toxicity tests were performed. The results were subjected to the probit analysis to determine the 96hLC50 values. Therapeutic index (TI) was calculated with respect to short-term LC50 and effective therapeutic concentrations commonly used for fish treatment. RESULTS: The mean 96hLC50 values for sodium chloride were 21.69 +/- 0.92 g l-1 (TI = 1.4) for P. reticulata and 10.39 +/- 0.12 g l-1 (TI = 1.0) for D. rerio. The acute toxicity of formaldehyde for D. rerio expressed as 96LC50 was 0.12 +/- 0.003 ml l-1 (TI = 5.24) and for P. reticulata 0.1 +/- 0.003 ml l-1 (TI = 4.9). The acute toxicity of potassium permanganate for D. rerio expressed as 96LC50 was 1.25 +/- 0.15 mg l-1(TI = 1.5) and for P. reticulata 1.43 +/- 0.05 mg l-1 (TI = 2). CONCLUSION: P. reticulata showed significantly higher (p < 0.05) tolerance to sodium chloride than D. rerio, whereas D. rerio showed significantly higher (p < 0.05) tolerance to formaldehyde than P. reticulata. The acute toxicity of potassium permanganate was comparable for both fish species. Calculated therapeutic indexes of all tested substances were low; therefore it is important to conduct preliminary tolerance tests before application of treatment baths.

Comparison of acute toxicity of 2-phenoxyethanol and clove oil to juvenile and embryonic stages of Danio rerio.

OBJECTIVES: Anaesthetics are used in aquaculture to prevent stress and mechanical damage to fish during handling or the treatment of fish in breeding, blood sampling and other veterinary interventions. Clove oil and 2-phenoxyethanol are used in the Czech Republic in a water bath for the short-term immobilization of the fish. DESIGN: Acute toxicity tests were performed on aquarium fish Danio rerio, which is considered to be one of the model organisms most commonly used in toxicity testing. The semi-static method according to OECD No. 203 (Fish acute toxicity test) was used for testing juvenile fish. Embryo toxicity tests were performed in zebrafish embryos (D. rerio) in compliance with the OECD No. 212 methodology (Fish, short-term toxicity test on embryo and sac-fry stages). The results obtained (the number of dead individuals at particular test concentrations) were subjected to a probit analysis using the EKO-TOX 5.2 programme in order to determine LC50 clove oil and 2-phenoxyethanol values. The statistical significance of the difference between LC50 values in juvenile and embryonic stages of D. rerio was tested using the Mann-Whitney non-parametric test implemented in the Unistat 5.1 programme. RESULTS: The LC50 clove oil mean value was 18.8 +/- 5.52 mg.L-1 in juvenile D. rerio, and 15.64 +/- 3.30 mg.L-1 in embryonic stages of D. rerio. The LC50 2-phenoxyethanol mean value was 338.22 +/- 15.22 mg.L-1 in juvenile D. rerio, whereas in embryonic stages of D. rerio it was 486.35 +/- 25.53 mg.L-1. CONCLUSIONS: The study proved statistically significantly higher (p<0.01) sensitivity in juvenile fish to 2-phenoxyethanol compared to the embryonic stages. Acute toxicity values of clove oil for juvenile and embryonic stages were comparable.

Comparison of the sensitivity of Danio rerio and Poecilia reticulata to silver nitrate in short-term tests.

The aim of this study is to assess the acute toxicity of silver nitrate in adult zebra fish and adult guppies and to compare the sensitivity of these species to this compound. Silver is a naturally occurring element in our environment and it combines with other elements such as sulfide, chloride, and nitrate. Silver, in the form of silver nitrate, is one of the most toxic metals affecting freshwater fish. Industry, particularly photographical and electrotechnical, is the major contributor of silver that is released into the environment. Tests of acute toxicity were performed on the most common species of aquarium fish, Danio rerio and Poecilia reticulata. Both zebra fish and guppies were exposed to progressive concentrations of silver nitrate; a semi-static method according to OECD 203 was used. In each test series, 6 tests of acute toxicity were conducted, with 10 fish used for each separate concentration and for the control group. The results (number of fish deaths in the individual test concentrations) were subjected to probit analysis (EKO-TOX 5.1 software) to determine the 96hLC(50) AgNO(3) values. The 96hLC(50) AgNO(3) value for the zebra fish was (mean±SEM) 15±0.52 µg/l and for the guppies was (mean±SEM) 17.14±5.43 µg/l. We didn't find any statistically significant difference between the sensitivity of zebra fish and guppies. The results reported in this study are in agreement with LC(50) values published in peer-reviewed literature, and conclude that AgNO(3) is one of the most toxic compounds known to fishery.