Delano Dias Schleder

O trabalho avaliou a suplementação na dieta de óleo essencial de C. longa sobre os parâmetros zootécnicos e hematológicos de tilápia-do-nilo (Oreochromis niloticus) em sistema de bioflocos e sua sobrevivência após infecção por Streptococcus agalactiae. Um total de 240 peixes foram divididos em 2 tratamentos: TR1 = 0% e TR2 = 0,1% (óleo essencial de C. longa) divididos em 8 caixas, 30 peixes em cada e alimentados durante 60 dias. Após o período de alimentação foram avaliados os parâmetros hematológicas e de desempenho zootécnico. Ao final foi realizado desafio experimental com a bactéria S. agalactiae. As tilápias foram infectadas com a bactéria através de injeção intraperitoneal, e a mortalidade monitorada durante 10 dias. Os parâmetros hematológicos da tilápia-do-nilo não apresentaram diferenças estatisticas significativas entre os tratamentos, com exceção da hemoglobina que foi significativamente superior nos peixes alimentados com ração suplementada com óleo essencial. Os resultados de peso final, ganho de peso semanal, taxa de crescimento específico e produtividade foram significativamente maiores nos peixes do grupo controle. No teste de desafio, as tilápias alimentados com óleo essencial apresentaram sobrevivência de 96 % em relação as não alimentadas com óleo, com uma sobrevivência de 79 %, o que representa uma diminuição de quase 17 % na sobrevivência. O estudo mostrou que o óleo essencial de Curcuma longa aumenta a resistência à estreptococose em tilápia, demonstrando o papel antibacteriano dessa espécie vegetal.

Aquaculture continues to expand globally and is now responsible for providing more than half of the aquatic products consumed worldwide

Shrimp farming is practiced worldwide in tropical and subtropical regions, where shrimp often experience suboptimal temperatures during part of the production cycle, resulting in slower growth. A concentrated functional palatability enhancer (FPE) containing a mixture of chemoattractants was tested. A 12-week experiment at a suboptimal temperature (22 °C) was conducted with Penaeus vannamei (3.25 ± 0.02 g) in a clear water system (400 L with 40 shrimp per tank) with flow-through seawater. A standard diet was supplemented with 0, 1, and 2 g kg⁻¹ of FPE (STD, STD+1, and STD+2) with four replicates for each one. The inclusion of 1 g kg⁻¹ of FPE (STD+1) significantly increased the average final weight by 11.24% and weekly weight gain by 14,00% when compared to STD. The highest tested dose (2 g kg⁻¹) did not result in further improvement in growth performance compared to the control. In addition, the total hemocyte count (THC) remained at an optimal level for the species in the STD+1 treatment under suboptimal temperature conditions compared to the other treatments. We also observed a decrease in Vibrio spp. bacterial counts in STD+1 compared to STD+2. Therefore, the lowest tested dose was shown to positively influence the rearing of P. vannamei at suboptimal temperatures.

O objetivo deste estudo foi avaliar a utilização de diferentes concentrações do óleo essencial de Curcuma longa como aditivo alimentar sobre os parâmetros hematológicos e zootécnicos de tilápia-do-nilo (Oreochromis niloticus). Foram utilizados 160 peixes, com peso médio de 82,96 ± 1,16g, os quais foram distribuídos aleatoriamente em quatro tratamentos: 0,0 (controle); 0,1%; 0,2% e 0,4% de óleo essencial de C. longa por kg de ração comercial, alimentados três vezes ao dia (8h, 12h e 17h), por 33 dias. Ao final do experimento, foram avaliados os parâmetros zootécnicos: sobrevivência, peso final, produtividade, taxa de crescimento específico, e os parâmetros hematológicos: hematócrito, número de eritrócitos, concentração de hemoglobina, constantes corpusculares, contagem total e diferencial de leucócitos. Os parâmetros zootécnicos e hematológicos não apresentam diferenças significativas entre os tratamentos. Diante desses resultados, conclui-se que a inclusão da Curcuma longa nas concentrações testadas, por um período de 33 dias, não alterou o desempenho e os parâmetros hematológicos das tilápias, não trazendo melhorias para o estado de saúde da tilápia-do-nilo.

This study aimed to identify the predominant bacterial populations in sardine samples with high histamine content (≥ 200 mg*kg-1) and histamine-free (< 1 mg*kg-1). For this study, 1,000 g of muscle samples were collected from 40–45 sardines per batch, all obtained from the same supplier, fishing area and period, for histamine analysis. Samples (1 g) from five different batches with ≥ 200 mg*kg-1 of histamine (named histamine group) and five with < 1 mg*kg-1 (named no-histamine group) were submitted to microbial analysis by extracting the total DNA, followed by polymerase chain reaction of the V3-V4 region of 16S rRNA gene and Ilumina sequencing (Mi-Seq, paired-end). In total, 18 different operational taxonomic units were identified in all samples. Sardines with high histamine content exhibited lower microbial diversity and a higher abundance of the genera Photobacterium and Shewanella. These bacteria thrive under mild temperatures and indicate fish spoilage and the production of biogenic amines. In contrast, Psychrobacter and Pseudoalteromonas, known to withstand harsh conditions, including low temperatures, were more prevalent in histamine-free sardines. Our findings point out to a marked change in the bacterial community of sardines with high and no histamine content, even though they are from the same fishing area, period, and shipment.

In the present study, Curcuma longa (CL) hydrolate and the probiotic Lactobacillus plantarum (LP) were provided as dietary supplements to Nile tilapia. One hundred ninety-two juvenile tilapias (2.25 ± 0.14 g and 4.5 ± 0.10 cm) were distributed in sixteen experimental units, and four experimental groups were established: CL [CUR]: fish fed a diet supplemented with CL hydrolate at 2.5%; probiotic [PRO]: a diet supplemented with LP; LP + CL [COMB]: diet supplemented with the LP strain cultivated in media supplemented with 2.5% CL hydrolate; and control [CTRL]: diet without supplementation. After 70 days, the final average weight was significantly greater in the PRO group (33.26 ± 1.12 g) than in the CTRL and CUR groups, whereas the specific growth rate was significantly greater in the PRO and COMB groups than in the CTRL and CUR groups. Feed conversion decreased significantly in the PRO group (1.03 ± 0.11). Dietary supplementation did not change the body composition of tilapia. Leukocyte and lymphocyte counts were greater in the PRO treatment than in the CTRL group. Compared with those in the CTRL group, total serum protein was significantly increased in the PRO group. Immunoglobulins were higher in the COMB and PRO groups. In the experimental challenge, all the fish in the treated groups presented lower cumulative mortality rates. The combination of LP and CL improved the growth parameters of Nile tilapia.

This study investigated the resistance of Pacific white shrimp (L. vannamei) to hypothermal shock when treated with extracts from the brown seaweeds Sargassum filipendula and Ascophyllum nodosum, either by immersion for postlarvae or as a dietary supplement for juveniles. Post-larvae were exposed to seaweed extracts at concentrations of 20, 50, 100, and 200 mg*L⁻¹, while juveniles were fed diets with 0.5%, 2.0%, and 4.0% seaweed extracts for 10 days. For juveniles (~12 g), hemato-immunological and microbiological analyses were conducted after feeding with 5% seaweed diets for 15 days, all followed by hypothermal shock. Samples were collected prior to the start of thermal shock, immediately after shock (0 h), and 1 and 24 h after return to initial temperature. The aqueous extract of the seaweeds A. nodosum and S. filipendula at concentrations 100 mg*L⁻¹ and 200 mg*L⁻¹, respectively, improves the survival rates of post-larvae L. vannamei submitted to hypothermal stress. For juvenile shrimps, hypothermal shock causes significant immunodepression and reduces the bacterial community in the intestine. The addition of seaweed to the feed did not increase the survival rate and did not affect the intestinal microbiota of L. vannamei. In the case of immunological parameters, both species positively affect the agglutination titer, but no other parameters analyzed.

This study investigated the effects of dietary supplementation with inactivated Lactobacillus plantarum for Nile tilapia (Oreochromis niloticus). Three treatments, in quintuplicate, were established: a control group, fish fed a diet without additives; LP group, fish fed a diet supplemented with live probiotic; and IP group, fish fed a diet supplemented with inactivated probiotic. Final weights (49.40 ± 3.15 g) and weight gains (38.20 ± 3.23 g) were increased in tilapia in the IP group. Feed conversion (1.32 ± 0.04) decreased significantly in the IP group. Haemato-biochemical parameters were significantly influenced by dietary supplementation. Erythrocyte count (262.74 ± 69.28 × 106 μL⁻¹) was significantly low, while albumin (1.79 ± 1.12 g dL⁻¹) and cholesterol (254.14 ± 98.49 mg dL⁻¹) were high in the control group. Dietary supplementation modified the tilapia microbiome. Rhodobacter was abundant in fish intestines from the control and IP groups. Phreatobacter was abundant in the IP and LP groups, while Aurantimicrobium and Bosea were abundant in the LP group. Oleic acid (C18:1n9) was significantly increased in the LP (3.25 ± 0.49%) and IP (3.02 ± 0.30%) groups. Hexadecatrienoic acid (C16:3n4) was significantly increased (0.04 ± 0.01%) in the IP group, while Cis 11,14,17-eicosatrienoic acid (C20:3n3) (0.31 ± 0.03%) and adrenic acid (C22:4n6) (0.11 ± 0.02%) were significantly decreased in the LP group. Additionally, monounsaturated fatty acids (MUFA) were significantly increased (4.83 ± 0.35%) in the LP group compared to that in the control group. Collectively, these results indicate the potential of inactivated L. plantarum for use in commercial feed, leading to the conclusion that both inactivated and live L. plantarum can improve the Nile tilapia metabolism, altering haematological and biochemical markers.