BACKGROUND: Tilapia, Oreochromis niloticus, is an omnivorous and important breeding species in the world. Over the recent years, tilapia breeding has begun in Iran. In aquaculture, it is very important to regulate a balanced diet in terms of nutrients needed for growth, which would be also economically appropriate.OBJECTIVES: The main objective of this study was to investigate the effect of substituting chicken waste powder in the diet of fish at levels of 0, 25, 50, 75, and 100 % on the tissue structure of different parts of the intestine of Nile tilapia.METHODS: 75 fish (three frequency per treatment) were fed with chicken waste powder instead of fish meal in their diet for eight weeks at 0, 25, 50, 75, and 100 % levels. At the end of the treatment, separate samples were taken from the initial, middle, and end parts of the intestine. After passing the usual histological steps, the slides were assessed by hematoxylin-eosin staining and TUNEL immunohistochemistry technique.RESULTS: In histometric studies, the highest villi height, thickness, muscle layer, and number of goblet cells were reported in the control group and the lowest in the 100 % group. In immunohistochemical studies, the number of apoptotic cells in groups 75 and 100 % was higher than that in the other groups.CONCLUSIONS: According to the results of the present study, it could be suggested that the replacement of chicken waste powder instead of a fish meal up to 50 % for indigo tilapia is tolerable. However, higher levels of chicken waste powder will reduce absorption, and acceptance of food and have adverse effects on growth.

BACKGROUND: Vitamin C is one of the important nutrients in fish culture and as a potent anti-oxidant, is of great importance in preserving cells against oxidation and boosting resistance in stress conditions and against pathogens. OBJECTIVES: The purpose of the present study is to add high level of vitamin C supplementation to rainbow trout (Oncorhynchus mykiss) diet reared at high density and analysis of growth indices, survival and carcass composition at two different stocking densities. METHODS: Rainbow trout juveniles with initial body weight of 9.6 ± 0.69 g at two densities of 50 and 100 pieces in 50 liters of water were fed two diets containing the same level of protein and fat. Experimental diets were diet 1 without adding vitamin and diet 2 with adding 1500 mg/kg of vitamin C. A total number of 900 rainbow trout juveniles in four treatments each with three replicates as T50 (0) (with the density of 50 and fed with diet 1), T100 (0) (with the density of 100 and fed with diet 1), T50 (C) (with the density of 50 and fed with diet 2) and T100 (C) (with the density of 100 and fed with diet 2) were randomly distributed in incubators. RESULTS: After 6 weeks of feeding, growth indices, feed conversion ratio and viability were significantly different between treatments (p<0.05). T50 (0) and T50(C) treatments had higher weight gain, specific growth rate and viability than T100 (0) and T100(C) (p<0.05). In the case of feed conversion ratio, it was higher in T100 (0) and T100(C) treatments compared to T50 (0) and T50(C) ones (p<0.05). Carcass composition was not significantly different between treatments (p>0.05). CONCLUSIONS: The results showed that vitamin C supplementation in the diet of rainbow trout juveniles did not have significant effects on growth indices, feed conversion ratio, survival and carcass composition but density was a key factor in growth, feed conversion ratio and survival in this species.

Hyperxanthinuria and xanthine uroliths have been recognized with increased frequency in dogs with ammonium urate uroliths that had been given allopurinol. We hypothesized that dietary modification might reduce the magnitude of uric acid and xanthine excretion in urine of dogs given allopurinol. To test this hypothesis, excretion of metabolites, volume, and pH were determined in 24-hour urine samples produced by 6 healthy Beagles during periods of allopurinol administration (15 mg/kg of body weight, PO, q 12 h) and consumption of 2 special purpose diets: a 10.4% protein (dry matter), casein-based diet and a 31.4% protein (dry matter), meat-based diet. Significantly lower values of uric acid (P = 0.004), xanthine (P = 0.003), ammonia (P = 0.0002), net acid (P = 0.0001), titratable acid (P 0.0002), and creatinine (P = 0.01) excreted during a 24-hour period were detected when dogs consumed the casein-based diet and were given allopurinol, compared with the 24-hour period when the same dogs consumed the meat-based diet and were given allopurinol. For the same 24-hour period, urine pH values, urine volumes, and urine bicarbonate values were significantly (P = 0.0004, P 0.04, and P = 0.002, respectively) higher during the period when the dogs were fed the casein-based diet and given allopurinol than when they were fed the meat-based diet and given allopurinol. Endogenous creatinine clearance was significantly (P = 0.006) lower when dogs were fed the casein-based diet and given allopurinol than when they were fed the meat-based diet and given allopurinol. Significantly lower concentrations of plasma uric acid (P 0.0001), plasma xanthine (P = 0.01), and serum urea nitrogen (P = 0.0001) were detected when dogs consumed the casein-based diet and were given allopurinol than when they consumed the meat-based diet and were given allopurinol.

Two diets similar in caloric density and mineral content, but markedly different in protein content, were used to study the effects of dietary protein on renal function and morphologic and histopathologic changes in dogs that had functional renal tissue reduced by seven-eighths nephrectomy. The effects of moderate protein intake (MPrI = 15% protein; dry-matter basis) and high-protein intake (HPrI = 31% protein; dry-matter basis) were studied for the initial 7 months (period 1 [P1]) after renal mass reduction. Diets were then switched between groups during the following 7 months (period 2 [P2]) to evaluate the effects of increased or decreased protein intake. The HPrI caused significantly (P < 0.05) greater glomerular filtration rate (GFR) and renal growth than did MPrI during P1. Dogs that maintained HPrI during P1 and MPrI during P2 (group 1) had significant (P < 0.05) reduction in GFR during P2. Dogs that maintained MPrI during P1 and HPrI during P2 (group 2) had significant (P < 0.05) improvement in GFR and renal growth during P2. At the end of the study, renal reserve was evaluated in both groups of dogs before and after group 1 was returned to HPrI for 2 weeks. During this 2-week feeding trial, group-1 dogs had marked improvement in renal reserve, relative to group 2, and GFR increased to the terminal P1 values. Results indicate a possible residual benefit from HPrI during the early phase of compensatory renal growth in the form of functional compensatory memory to HPrI. The severity of renal lesions was indistinguishable between dogs of dietary groups during both study phases. Plasma electrolyte concentrations rapidly returned to normal range after renal ablation, but mild azotemia and proteinuria persisted throughout most of the study. High protein intake was not associated with increased degree or progression of proteinuria.

Introduction: In the European Union, the use of thyreostatic drugs for fattening slaughter animals has been banned since 1981 under Council Directive 81/602/EEC. For protection of consumer health against unwanted residues and in compliance with Directive 96/23, each EU country must monitor thyreostats in samples of animal origin. This paper presents the results of research on thyreostatic residues carried out in Poland in 2011–2017. Material and Methods: The material for testing was urine (n = 3,491), drinking water (n = 127), and muscle samples (n = 349) officially collected by Veterinary Sanitary Inspectors in slaughterhouses and farms throughout the country in accordance with the national residue control plan. The samples were examined for the presence of tapazole, thiouracil, methylthiouracil, propylthiouracil, and phenylthiouracil using liquid chromatography tandem mass spectrometry through an accredited method. Results: In four bovine and three porcine urine samples, the permissible thiouracil concentration was exceeded. In one sample of porcine urine, methyl- and propylthiouracil were found. The presence of thiouracil and its derivatives in urine samples is most likely due to feeding animals diet containing cruciferous plants. Conclusions: The results of research indicate that thyreostats are not used for anabolic purposes in slaughter animals in Poland.

There is a balance between oxidative stress, antioxidant capacity and immune response. Their roles in physiological and behavioural mechanisms are important for the maintenance of the organism’s internal equilibrium. This study aimed to evaluate the antioxidant effects of the exogenous alga Spirulina platensis (Arthrospira platensis) in a stress-induced rat model, and to describe its possible mechanism of action. Thirty-six adult male Sprague Dawley rats were separated into four groups: control (C), stress (S), S. platensis (Sp), and S. platensis + stress (SpS). The rats in groups Sp and SpS were fed with 1,500 mg/kg b.w./day Spirulina platensis for 28 days. All rats were exposed to prolonged light phase conditions (18 h light : 6 h dark) for 14 days. The SpS and S groups were exposed to stress by being kept isolated and in a crowded environment. Blood samples were obtained by puncturing the heart on the 28th day. The effect of stress on serum corticosterone, oxidative stress markers (TOS, TAC, PON1, OSI) and immunological parameters (IL-2, IL-4, IFN-ɣ) were tested. Also, the brain, heart, intestines (duodenum, ileum, and colon), kidney, liver, spleen, and stomach of the rats were weighed. Serum corticosterone levels were higher in the S group than in the C group, and significantly lower in the SpS group than in the S group. Mean total antioxidant capacity were lower in the S group than in the C group, and Spirulina reversed this change. Although not significantly different, IL-2 was lower in the S group than in the C group. However, in the SpS group, IL-2 increased due to Spirulina platensis mitigating effects of stress. Male rats fed a diet with Spirulina platensis could experience significantly milder physiological changes during stress, although stress patterns may be different. Exogenous antioxidant supplements merit further investigation in animals and humans where the endogenous defence mechanism against stress may not be sufficient.

For many years, scientists have been pursuing research on skeletal muscle ageing both in humans and animals. Studies on animal models have extended our knowledge of this mechanism in humans. Most researchers agree that the major processes of muscle ageing occur in the mitochondria as the major energy production centres in muscle cells. It is believed that decisive changes occur at the enzymatic activity level as well as in protein synthesis and turnover ability. Deregulation of ion channels and oxidative stress also play significant roles. In particular, in recent years the free radical theory of ageing has undergone considerable modification; researchers are increasingly highlighting the partly positive effects of free radicals on processes occurring in cells. In addition, the influence of diet and physical activity on the rate of muscle cell ageing is widely debated as well as the possibility of delaying it through appropriate physical exercise and diet programmes. Numerous studies, especially those related to genetic processes, are still being conducted, and in the near future the findings could provide valuable information on muscle ageing. The results of ongoing research could answer the perennial question of whether and how we can influence the rate of ageing both in animals and humans.

The aim of the study was to determine the effects of supplementation of sows’ and growing pigs’ diets with three newly developed synbiotic and two extant commercial probiotic products on selected immune parameters under field conditions. The study was performed on 30 sows and 48 piglets of the Danbred breed. Immune parameters such as concentration and proportion of white blood cells and their subpopulations, immunoglobulins amount in serum, and serum concentration of cytokines and acute phase proteins were recorded with the use of a haematology analyser and ELISA kits. No significant differences between treatment groups and controls were found with regard to the immune parameters evaluated except for serum immunoglobulin concentration, which was significantly increased by synbiotic products B and C and probiotic product D. The results of the study indicate that the synbiotic products B and C and probiotic product D are worthy of further investigation as promising candidates to improve the immune status of healthy sows and their offspring.

OBJECTIVE To determine whether blood taurine concentrations in dogs with exocrine pancreatic insufficiency (EPI) were lower than the reference interval (200 to 350 nmol/mL) or the cutoff used to indicate taurine deficiency (< 150 nmol/mL). ANIMALS 18 dogs with clinical or presumptive subclinical EPI with residual blood samples available for taurine concentration analysis. PROCEDURES Dogs were classified as having clinical EPI if they had a serum trypsin-like immunoreactivity concentration of < 2.0 μg/L and presumptive subclinical EPI if they had a concentration of 2.0 to 5.0 μg/L. Archived, frozen blood samples stored in EDTA were submitted for measurement of taurine concentration with an automated high-performance liquid chromatography amino acid analyzer. Medical record data were examined for associations with blood taurine concentration. RESULTS None of the 18 dogs had a blood taurine concentration < 150 nmol/mL. Two dogs had a concentration < 200 nmol/mL. No clinical signs, physical examination findings, or serum biochemical abnormalities were associated with blood taurine concentration. Eleven of the 17 dogs for which diet histories were available were not receiving a diet that met recommendations of the World Small Animal Veterinary Association Global Nutrition Committee. CONCLUSIONS AND CLINICAL RELEVANCE A low blood taurine concentration was noted in a small subset of dogs with EPI. Additional research is needed to determine whether EPI was the primary cause of this low concentration. Findings suggested the importance of obtaining complete diet histories and ensuring dietary requirements are sufficiently met in dogs with EPI.