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The present study was carried out to determine the effect of tilapia Oreochromis niloticus on the physical and chemical sediment parameters on an earthen pond in monoculture (shrimp Penaeus vannamei) and co-culture (tilapia-shrimp) during the dry and wet seasons in a commercial farm during the period from mid-September to end-December 2017 and February to mid-May 2018. Chemical and physical analyses were realized on sediment samples from brackish water ponds representing shrimp farms in San Blas Nayarit, Mexico. Concentrations of organic carbon, nitrogen, potassium, magnesium and calcium were higher in co-culture ponds, and there was a tendency to a higher concentration of phosphorus and sodium in the sediment of monoculture ponds. The texture of the ponds showed a tendency in the dry season to increase the percentage of clay in co-culture due to the effect of bioturbation caused by tilapia. There was no evidence of poor development of sediment quality in any treatment. It was found that tilapia was a factor that affected sediment quality, differences in growth between shrimp monoculture and tilapia-shrimp co-culture can be explained, at least in part, by differences in their sediment.

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This study was performed to investigate the effect of different levels of aspirin on the diet of broilers. The experiment was conducted in a completely randomized design using 120 one-day-old male broiler chicks of commercial Ross 308 strain to study the effects of three different levels of aspirin (0, 50 and 100 mg/kg) in 3 treatments, in 4 replicates, each including 10 chicks, during 42 days. The effects of different levels of aspirin, added to a basic diet, on performance, carcass characteristics and digestive organs, blood plasma components, liver enzymes, immune system, secal microflora, and acid profile of breast meat of broiler chickens were investigated. Data analysis was performed by SAS statistical software and the comparison of the means with Duncan's multiple-range test at 5% probability level. The results showed that in the final period, the chickens fed by a diet containing 100 mg/kg of aspirin (A) had the highest feed intake and weight gain and the best feed conversion ratio compared to the other treatments. Also, according to the tables, the lowest production cost and the best European factor were related to treatment A100, which was statistically significant compared to the control (P < 0.05). In addition, the use of the same level of aspirin resulted in a significant increase in some carcass properties and a decrease in ventricular fat compared to the control (P < 0.05). On the other hand, the effects of using two different levels of aspirin on blood parameters and liver enzymes of broilers except for alkaline phosphatase were not significant throughout the period (P ≥ 0.05). Also, the use of the same level of aspirin had no significant effect on the function of the humoral immune system in response to antigen injection, antibody titer against sheep red blood cells (SRBC) and antibody titer against Newcastle disease and influenza virus (P ≥ 0.05). But according to the table, the highest percentage of neutrophils and eosinophils was related to this treatment. Also, aspirin treatments increased the levels of unsaturated fatty acids and decreased saturated fatty acids. Moreover, aspirin treatment led to a reduction in the population of Escherichia coli. So, based on the results of the present study, the use of 100 mg/kg aspirin in the diet of broilers is recommended.