The main aimed of this study was to provide information on microplastics present in the freshwater of fish farm ponds. In addition, the study showes a relationship between the seasonal, spatial distribution and the amount of microplastics found. This study was conducted in 35 fish farms located in the Rondônia state, Brazil, the sample collects were carried out in the two Amazonian hydrological seasons (dry and rainy). The study was developed in a completely randomized factorial scheme 35 × 3 x 3 (35 fish farms, 3 ponds and 3 repetitions per ponds). Microplastic sampling was performed following a modified method based on National Oceanic and Atmospheric Administration (NOAA). Samples of 250 mL freshwater collected, which were deionized and pre-filtered through 6.0 mm mesh granulometric sieves. The average abundances of the different hydrological seasons were compared by Student's t-test, with differences statistically significant at p < 0.05. The microplastics were morphological categorized into fibers and colors blue, red or transparent. Microplastic contamination was confirmed in freshwater of 9 fish farming, with greater abundance of blue fibers and greater quantification in the rainy season. Fish farms P3, P4 and P6 had the highest quantifications of blue fiber in the two seasons (6 and 43, 19 and 56, 11 and 88 items mL⁻¹, respectively). Almost all fish farms had a higher abundance of microplastics in the rainy season. It is important to highlight the prominence of microplastics in the blue fiber rainy season (286 items mL⁻¹) compared to the dry season (58 items mL⁻¹). Fish farms P3, P4 and P6 showed a strong positive correlation between the factors distance from the nearest urban area (r = 0.94, 0.79 and 0.97, respectively) and seasonality (r = 0.98, 0.77 and 0.96, respectively). Rainfall variations influenced the abundance of microplastics, especially of blue fibers. Fish farms are supplied with fresh water by rivers or streams, so it is possible that microplastics originate outside the fish farm, perhaps they were introduced due to high soil occupation, although surface runoff (of water contaminated by sewage) caused by heavy rains the most important factor. Therefore, one factor must be considered, surface runoff and groundwater contaminated by urban, agricultural and urban effluents may have contaminated rivers and streams and then contaminated the water in the fish farm ponds.

The agricultural industry is the main emitter of methane (CH4) and nitrous oxide (N2O), gases that each have a global warming potential that is greater than that of CO2 by 23 and 298 times, respectively. On a global scale, enteric fermentation from ruminant animal production (especially of cattle and sheep) is responsible for between 21% and 25% of total anthropogenic CH4 emissions. The search for effective, simple, and fast methods to measure the production of CH4 and other products from ruminal fermentation has been the objective of several studies on ruminant nutrition. Thus, techniques have been developed under experimental conditions of Brazil and other international countries to quantify CH4 emissions of ruminants. The objective of this literature review is to discuss and compare the existing techniques of measuring enteric CH4 from ruminants. Each technique has a shortcoming or disadvantage in its characterization of ruminal fermentation. The ex-situ technique of measuring CH4 from ruminal fermentation has been quite promising, because it facilitates the measurement of CH4 and other fermentation products, such as short chain fatty acids (SOFA). CH4 detection by a portable laser is effective in monitoring fluctuations in emission and is recommended especially for short-term measurements of respiring and eructating animals reared in a feedlot system. Other methods are being improved and better adapted for practical use in the ongoing quest for more efficient uses of ruminal fermentation products.

The aimed of the study was to evaluate the caloric value as a function of the proximal composition and correlate the selling price with the nutritional values ​​of commercial cuts of tambaqui (Colossoma macropomum) and pirarucu (Arapaima gigas) in different weight classes. The sample collections were performed in two processing units located in the state of Rondônia, Brazil. Were 200 tambaquis in five weight classes were studied. And, were 77 pirarucus were studied in seven weight classes. The design was completely randomized, with processing carried out in triplicate. The Kruskal-Wallis test (α=0.05) was used to compare the averages and the Spearman correlation (ρ) between price and nutrients. The commercial cuts with the highest caloric value were the tambaqui filet (145.70 kcal/100g) and the pirarucu filet mignon (119.11 kcal/100g) (p<0.05). And the less caloric commercial cuts were steak of tambaqui (100.47 kcal/100g) and pirarucu loin 102.01 kcal/100g) (p<0.05). It was also observed that the variables caloric value and protein content did not correlate with the price of the kilo of fish for the different commercial cuts, which leads to infer that, possibly, the sensorial, market and cultural factors were responsible for the price variations. Regarding the caloric value according to the composition of the tambaqui, the Class 4 was the most efficient category for production and commercialization. And in the composition of the pirarucu, the Class 4 presented satisfactory values of proteins and lipids and a good percentage of mineral matter.

With the intensification of fish farming, the amount of residues also increased. One of the by-products generated is leather. However, several factors influence its quality, among them, the types of tanning used. Paiche (Arapaima gigas) is the largest freshwater fish in the world, and therefore has great potential in the use of leather, in addition to being one of the most cultivated fish in the Rondônia state. The aimed was to evaluate the physicomechanical resistance, histological and morphological aspects in different directions of the fibers of the paiche to evaluate the tanning with chromium oxide and vegetable tannin. Paiches with an average weight of 12.0 kg were used, skins were made and tanned using chromium and vegetable tannin as techniques. After tanning, 20 specimens were removed in longitudinal, transverse and diagonal directions to the fish body, to determine resistance in dynamometer and leather for histological analysis, scanning electron microscopy and physical-chemical analysis. The average thickness of the specimens of the leathers ranged 1.79mm to 2.82mm, in addition, there was no interaction between the type of tanning agent and the directions obtained for strength, traction and elongation. Regarding the progressive tearing test, there was also no interaction effect. However, the defined factors had relevant differences for the maximum and average amount applied, and the leathers tanned with vegetable tannin expanded to larger dimensions 110.19 and 85.52 N. According to the images obtained by histology and scanning microscopy, they presented that in the longitudinal and transverse direction the collagen fibers are presented in layers parallel to the leather surface and in the diagonal direction the interlacing is more intense, that is, in addition to the overlapping layers intercalated thinner, close to the surface, fiber bundles can also be seen crossing each other. It is concluded that leathers tanned with vegetable tannin have less resistance than leathers tanned with chromium salts for traction to rupture and greater resistance to tear.

The study's aim was to evaluate the microbiological, nutritional, textural quality and palatability of pet biscuits made with the inclusion of three flours. The treatments were chicken viscera flour (CVF), commercial Nile tilapia flour (FF) and mixed fish flours of several species (FVF). For the FVF, only the carcasses (backbones) of Nile tilapia, salmon, tuna and sardines were used, and they were washed, whereas FVF as well as the others were cooked for 60 minutes, then pressed, ground and dehydrated for 24 hours at 60° C. After this period, they were crushed and ground for inclusion in the biscuits. The CVF, FF and FVF flours showed 43.82%, 50.48% and 56.70% of crude protein, respectively. CVF had the highest lipid content (10.01%) and FVF had the highest ash content (23.94%) and FVF had the highest caloric value (338.63 kcal 100 g^-1). The inclusion of flours in biscuits did not influence the protein and carbohydrate contents, whose average values ​​were 18.48% and 50.23%. However, they influenced the moisture content, lipids, ash and caloric value. Biscuits with the inclusion of viscera (CVF) had the highest lipid content (5.91%) and those with fish had the highest ash content (5.66% and 5.81%) for FF and FVF. Biscuits with FVF had a lower caloric value (318.47 kcal 100 g^-1). The microbiological analysis indicated that the biscuits were considered of good quality to feed dogs. Regarding texture and palatability, there was no significant difference between treatments. The inclusion of fish flour, both FF and FVF, is a viable alternative.