Nutritional value of potato tubers from field grown plants treated with deltamethrin

Summary Tubers showed changes in their nutritional value caused by the treatment of the plants with the insecticide deltamethrin. The level of starch was increased in comparison with control tubers; but the amylose percentage was not affected. In contrast, the total protein content decreased in tubers from treated plants, whereas free amino acids level and ascorbic acid content increased. The results showed that the changes in the tubers caused by the treatment of potato plants with deltamethrin did not adversely affect the nutritional value of the progeny tubers.     

Effects of rice bran protein concentrate on the growth performance and digestive enzyme activities of jundiá (Rhamdia quelen) (Quoy and Gaimard, 1824)

The aim of this study was to assess the effect of increasing inclusion levels (100, 150, 200 and 300 g/kg) of rice bran protein concentrate (RBPC) in jundiá (Rhamdia quelen) diets using growth, body composition, somatic indices and digestive enzyme activity as parameters. Five isoproteic (370.08 ± 0.04 g/kg) and isocaloric (13.38 ± 0.04 MJ/kg) diets were formulated with four replicates per treatment. After acclimation, 500 jundiá juveniles (initial mean weight of 6.28 ± 0.12 g) were distributed into 20 round polyethylene tanks (280 L) (25 fish per tank) coupled to a thermoregulated water recirculating system. The fish were fed experimental diets three times daily (at 9:00, 13:00 and 17:00 hr) to apparent satiation. At the end of the trial (45 days), no significant differences were found in the body chemical composition, somatic indices, and trypsin and chymotrypsin enzymes of the fish fed experimental diets. A lower final weight and a lower condition factor were found in fish fed diets RBPC10 (100 g/kg of RBPC) and RBPC15 (150 g/kg of RBPC). Based on the results of this study, it is clear that the use of RBPC (at high dietary inclusion levels of 200 and 300 g kg^?1) is an effective alternative protein source to fishmeal.     

Thyroid hormone‐induced swim bladder and eye maturation are transduced by IGF‐1 in zebrafish embryos

Maternally derived thyroid hormones (THs) deposited in yolk promote fish embryogenesis and survival, and understanding early regulatory mechanisms could lead to improved seedstock production. We have tested the hypothesis that some thyroid actions may be mediated by insulin‐like growth factor I (IGF‐1), another promoter of embryo development. Differentiation and performance were assessed in embryos treated with THs in the presence or absence of an IGF‐1 receptor blocking peptide. Treatment with the TH triiodothyronine (T₃) promoted IGF‐1 gene expression at days 1 and 5, and advanced swim bladder and eye development, but blocking the IGF‐1 receptor eliminated the swim bladder and eye effects. Growth and survival at 1 week of age were impaired by the IGF‐1 receptor blocking peptide alone, but concurrent treatment with T₃ partially restored these indices. Our results confirm interaction of T₃ and IGF‐1 regulatory signalling in zebrafish embryogenesis and transduction by IGF‐1 of thyroid‐driven swim bladder and eye maturation.     

Effect of the Lactiplantibacillus plantarum and Lentilactobacillus buchneri on corn and sorghum silage quality and sheep energy partition under tropical conditions

This study aimed to evaluate the silage quality, ingestive behaviour, and sheep energy partition fed corn and sorghum silages, with or without inoculation with Lactiplantibacillus plantarum and Lentilactobacillus buchneri. Whole plants of one dent corn hybrid (DCS), one flint corn hybrid (FCS), and one forage sorghum hybrid (SS) were ensiled with or without an inoculant containing L. plantarum and L. buchneri (4 × 10⁵ CFU g⁻¹), totalling six treatments (3 × 2 factorial scheme). The treatments were ensiled in metal drums with 200 L capacity. The lactic acid concentrations in the inoculated FCS and DCS were higher by 13.4% and 12.8%, respectively, than those in the non-inoculated plants. In contrast, the lactic acid concentration in the inoculated SS was 23.1% lower than that in the non-inoculated SS. Furthermore, there were differences in pH and acetic acid concentrations only in SS, which were 2.3% and 45.2% higher, respectively, in inoculated silage than in non-inoculated silage. In inoculated DCS and SS, propionic acid concentrations were 1.7 times higher (for both silages), and 1-propanol was 3.7 and 1.8 times higher compared than those in non-inoculated silages. There was a main effect of the inoculant on 1,2-propanediol concentrations, which were 37.5% higher in inoculated silages than in non-inoculated silages. However, ingestive behaviour, heat and methane production, and silage net energy concentrations were not affected by inoculant use. Fermentative modifications caused by inoculation with L. plantarum and L. buchneri in whole plant corn or sorghum silage did not modify sheep energy partition.     

Technical and economic feasibility of integrating seahorse culture in shrimp/oyster farms

Integrated multi‐trophic aquaculture systems (IMTA) are building ecosystems designed to produce aquatic organisms with less environmental impact. We have developed a simple system and a management strategy for introducing seahorse (Hippocampus spp.) culture in shrimp/oyster farms to increase economic sustainability. The system includes broodstock, nursery and grow‐out phases of Hippocampus reidi G. culture. We performed a test in a 42.4‐ha marine shrimp/oyster farm, which showed that this system is technically feasible. Then, we performed a partial budget analysis including cost‐return, cash flow and financial feasibility analysis. More than 12 000 marketable size seahorses may be produced in 402 m² annually. Initial investment was only US$ 21 103.00. The benefit–cost ratio was ~US$ 20.00 for each US$ 1.00 spent, internal rate of return was 131% and payback period <2 years. In conclusion, the introduction of seahorse in shrimp/oyster IMTA system is technically feasible, profitable, resilient and shows high liquidity. This system may be easily established in developing countries and has potential to provide seahorses to supply different markets (live specimens for the marine aquarium trade and dried specimens for traditional Chinese medicine and the curio trade). In addition, it can indirectly contribute to preserve natural populations.     

Feeding selectivity in early life stages of Rhamdia voulezi under experimental conditions

The feeding selectivity of laboratory‐reared larvae of Rhamdia voulezi was assessed to investigate the preferred preys in early life stages. Three experiments were conducted at different larval development stages, starting soon after the absorption of the yolk sac (on fourth day after hatching – DAH), using zooplankton from fish ponds as food. Differences were detected in the patterns of prey selection among development stages. At first, the larvae prefer small preys, such as rotifers and cladocerans. Later, when they are more developed, they prefer to feed on large preys, such as copepods. On the fourth DAH, larvae in the pre‐flexion and initial flexion stage strongly selected rotifers and cladocerans (Diaphanosoma spinulosum, D. brevireme, Moina sp., M. micrura and M. minuta). At the other stages, cladocerans continued to be strongly selected. However, on the eighth DAH, larvae in flexion stage selected less strongly copepods Argyrodiaptomus azevedoi, Metacyclops mendocinus and Termocyclops decipiens. On the tenth DAH, larvae in postflexion stage selected more strongly copepods Argyrodiaptomus furcatus, Notodiaptomus cf. spinuliferus and M. mendocinus. As larvae grow, they tend to specialize in feeding of a particular prey. Prey selection of R. voulezi larvae was based both on species and zooplankton size. The size of the zooplankton ingested was related to the mouth gape size of larvae.     

Antibiotic resistance in potentially bacteriocinogenic probiotic bacteria in aquaculture environments

Bacteriocin‐producing bacteria in aquaculture may prevent spreading of potentially pathogenic microorganisms, and could be used as an alternative to the empirical use of antimicrobial drugs, especially for prophylaxis. Bacteriocinogenic bacteria inoculated as probiotics should not carry undesirable traits, such as antibiotic resistance. This study aimed to find potentially bacteriocinogenic bacteria in an aquaculture system and evaluate their antimicrobial susceptibility patterns. Selective cultures for enterobacteria, non‐fermenting Gram‐negative rods and Gram‐positive cocci were obtained from water samples before bacterial isolation and biochemical identification. Overall, 160 representative strains were recovered and for 57 antagonism was observed against selected strains such as Staphylococcus aureus, with antagonism being expressed better on Brain Heart Infusion medium. After exclusion of interfering factors, bacteriocin or bacteriocin‐like substances were suggested to be related to the antagonism observed. Higher drug‐resistant rates were observed among potentially bacteriocinogenic bacteria for different antimicrobials of clinical relevance. Although antibiotic resistance is a global health problem and bacteriocins are attractive alternatives to classical antibiotic even to multiresistant bacteria, the data obtained suggest that bacteriocin‐producing bacteria may harbour resistance genes available for transference in different environments. From the ecological and biotechnological perspective, antimicrobial susceptibility tests must be always performed when prospecting potentially bacteriocinogenic bacteria as probiotic candidates in the environment.     

Exploring Chemical Diversity of Phorbas Sponges as a Source of Novel Lead Compounds in Drug Discovery

Porifera, commonly referred to as marine sponges, are acknowledged as major producers of marine natural products (MNPs). Sponges of the genus Phorbas have attracted much attention over the years. They are widespread in all continents, and several structurally unique compounds have been identified from this species. Terpenes, mainly sesterterpenoids, are the major secondary metabolites isolated from Phorbas species, even though several alkaloids and steroids have also been reported. Many of these compounds have presented interesting biological activities. Particularly, Phorbas sponges have been demonstrated to be a source of cytotoxic metabolites. In addition, MNPs exhibiting cytostatic, antimicrobial, and anti-inflammatory activities have been isolated and structurally characterized. This review provides an overview of almost 130 secondary metabolites from Phorbas sponges and their biological activities, and it covers the literature since the first study published in 1993 until November 2021, including approximately 60 records. The synthetic routes to the most interesting compounds are briefly outlined.