The study aimed to investigate the effect of rosemary (Rosmarinus officinalis) extract on the quality changes of fishballs from knife fish (Chitala chitala) and striped catfish byproduct (Pangasianodon hypophthalmus) during frozen storage. Fishballs were supplemented with rosemary extracts at two concentrations of 13 mg/kg and 156 mg/kg. The control treatment was the sample without extract. The products were steamed, vacuum packed in PA bags and stored at a temperature from -18oC to -20oC. Sampling was done at 0, 30, 60, 90, 120, 150 and 180 days of storage period for analysis of pH, Total volatile base nitrogen (TVB-N), total viable bacteria count (TVC), pathogenic bacteria, sensory properties, peroxide value (PV), Thiobarbituric acid reactive substances (TBARs). Results showed that Escherichia coli and Salmonella spp. were absent in the fishballs, reflecting the safety of products for consumers. Adding rosemary extract at 156 mg/kg in fishballs displayed more effectiveness in inhibiting the formation of lipid oxidation and microbial growth when compared to the control sample during the frozen storage. Based on the results of physicochemical and sensory quality, the supplementation of rosemary extracts showed a significant promise for improving the quality of fishballs. Fishballs from knife fish and striped catfish by-products could be maintained their sensory properties and prolonged their shelf-life up to 180 days of frozen storage.

Florfenicol (FF) is one of the common antimicrobials used to control bacterial disease in shrimp aquaculture. This study aimed to determine the pharmacokinetics (PK) parameters of FF in white leg shrimp plasma, hepatopancreas and muscle as well as its residue depletion in shrimp muscle and the impact on shrimp hepatopancreas histology during and after FF medication. In the PK experiment, shrimp were fed once at 10 mg FF/kg body weight (bw) via oral in-feed administration to determine PK parameters in plasma, hepatopancreas and muscle. The maximum concentration (C_max) of 60.56 μg/L in plasma was observed after 1.77 h (T_max). In muscle, a C_max of 11.76 μg/kg was attained after 0.20 h, while in hepatopancreas, the C_max was higher (386.92 μg/kg) and was rapidly obtained (T_max = 0.19 h). The C_max values in shrimp plasma were below the minimum inhibitory concentration (MIC) against Vibrio parahaemolyticus, known to cause acute hepatopancreatic necrosis disease (AHPND) in shrimp. Therefore, it can be concluded that to ensure the effectiveness of this treatment, the dose should be higher than 10 mg FF/kg bw. FF depletion in white leg shrimp muscle and its histological impact on hepatopancreas were determined after feeding FF-medicated feed once-a-day or twice-a-day for 3 consecutive days with a dose of 10 mg FF/kg bw. The residues in shrimp muscle were rapidly eliminated and fell below the limit of quantification at 24 h after stopping medication. The withdrawal time of FF in shrimp muscle was 27.9 degree-days (2 days at 26.5 °C) according to the maximum residue limit (MRL) of 100 µg/kg set by the European Commission and Korean Ministry and when feeding FF twice-a-day for 3 days. The results from histological analysis showed that there was no negative effect on shrimp hepatopancreas after stopping medication in both once- and twice-a-day treatments.

A high-performance liquid chromatography method coupled to tandem mass spectrometry was validated in order to study the pharmacokinetics of cefotaxime in shrimp hepatopancreases and plasma, as well as its withdrawal time related to a maximum residue limit (MRL) in shrimp muscle. Pharmacokinetics parameters were investigated through oral medication at a single dose of 25 mg/kg shrimp body weight and subsequent hepatopancreas and plasma cefotaxime concentration measurements at 0.5, 1, 2, 4, 8, 12 and 24 h after shrimp were fed with medication. The maximum concentration of cefotaxime was observed after one hour in the hepatopancreas (C_max, 19.45 ± 2.10 mg/kg) and 4 h in plasma (0.184 ± 0.061 mg/L). Based on a minimum inhibitory concentration (MIC) of cefotaxime of 4.13 mg/L against Vibrio parahaemolyticus (known to cause acute hepatopancreatic necrosis disease (AHPND) in white leg shrimp), it was observed that the time during which the hepatopancreas cefotaxime concentration was above the MIC was 23 h. An every 24 h cefotaxime treatment could thus be effective in fighting against this bacterium in shrimp. The withdrawal time of cefotaxime was determined after shrimp were fed with medicated feed once a day and twice a day for three consecutive days. Shrimp muscle was collected on day 1 and day 3 during medication and 1, 3, 7, 14 and 21 days after medication was stopped. Considering an MRL of 50 μg/kg, the withdrawal times were 8.5 degree-days (corresponding to 6.9 h at 29.5 °C) after shrimp were fed with medicated feed once a day for 3 days and 95.5 degree-days (77.7 h at 29.5 °C) after shrimp were fed with medicated feed twice a day for 3 days. Moreover, histological analysis revealed that feeding shrimp with cefotaxime at the given dose in once- or twice-a-day treatments did not negatively impact the shrimp hepatopancreas.

This study investigated the effects of tea leaf (Camellia sinensis) extract on the quality of striped catfish (Pangasianodon hypophthalmus) fillets during 18-months of frozen storage (-20 ± 2 °C). Fillet samples were submitted to the treatments Control (cold tap water), CS 7.63 (C. sinensis extract solution 7.63 µg / mL) and CS 625 (C. sinensis extract 625 µg / mL) and stored for 18 months, with collections performed at 0, 1, 3, 6, 9, 12 and 18 months. Total viable count, physicochemical parameters (water holding capacity, total volatile basic nitrogen, peroxide value, thiobarbituric acid reactive substances, moisture and pH), sensory properties and color measurement were evaluated. Results showed that fillets treated with C.a sinensis extracts slightly reduced lipid oxidation, inhibited bacterial growth and improved sensory properties compared to untreated samples, without causing significant changes in the other quality indicators. The findings indicated that the green tea leaf extract immersion treatments, contributed to the improved quality preservation of striped catfish fillets during frozen storage.

This study aimed to determine pharmacokinetics (PK) parameters of FF in white leg shrimp plasma, hepatopancreas and muscle as well as its residue depletion in shrimp muscle and hepatopancreas, and the impact on shrimp hepatopancreas histology during and after FF medication. In the PK experiment, shrimp were fed once at 10 mg FF/kg body weight (bw) by oral in-feed administration to determine PK parameters in plasma, hepatopancreas and muscle. The maximum concentration (Cmax) of 60.56 μg/L in plasma was observed after 1.77 h (Tmax). In muscle, a Cmax of 11.76 μg/kg was attained after 0.20 h, while in hepatopancreas, the Cmax was higher (386.92 μg/kg) and was rapidly obtained (Tmax= 0.19 h). Cmax values in shrimp plasma were below the minimum inhibitory concentration (MIC) against Vibrio parahaemolyticus, known to cause acute hepatopancreatic necrosis disease (AHPND) in shrimp. FF depletion in white leg shrimp muscle and its histological impact on hepatopancreas were determined after feeding FF medicated feed once a day or twice a day for 3 consecutive days with a dose of 10 mg FF/kg bw. The residues in shrimp muscle were eliminated rapidly, and were below the limit of quantification at 24 h after stopping medication. The withdrawal time of FF in shrimp muscle was 27.9 degree-days (2 days at 26.5 °C) according to the maximum residue limit (MRL) of 100 µg/kg set by the European Commission and Korean Ministry when feeding FF twice a day for 3 days. The results from histological analysis showed that there was no negative effect on shrimp hepatopancreas after stopping medication.

This study aimed to investigate the effects of guava (Psidium guajava) leaf extract on the quality of striped catfish (Pangasianodon hypophthalmus) fillets during 18 months of frozen storage (-20±2°C). The study included three treatments, soaking striped catfish fillets in cold tap water as a control treatment, in 5.04 µg/mL Psidium guajava extract and in 313 µg/mL Psidium guajava extract. The samples were stored for 18 months and sampling was done at 0, 1, 3, 6, 9, 12 and 18 months. Evaluated parameters included total viable count (TVC), physicochemical parameters (water holding capacity (WHC), total volatile basic nitrogen (TVB-N), peroxide value (PV), thiobarbituric acid reactive substances (TBARs), moisture and pH), sensory properties and colour measurement. Results showed that striped catfish fillets treated with Psidium guajava extract reduced lipid oxidation inhibited bacteria growth, and enhanced sensory properties compared to untreated samples. In addition, treatment of Psidium guajava extract did not affect the pH, moisture, WHC, TVB-N and colour of fillets during frozen storage. Based on the total viable count, physicochemical parameters and sensory quality, it can be concluded that striped catfish fillets untreated or treated with Psidium guajava (5.04 and 313 µg/mL) extracts can be used for up to 18 months.