Moisture content monitoring in industrial-scale composting systems using low-cost sensor-based machine learning techniques.

Moisture is a key aspect for proper composting, allowing greater efficiency and lower environmental impact. Low-cost real-time moisture determination methods are still a challenge in industrial composting processes. The aim of this study was to design a model of hardware and software that would allow self-adjustment of a low-cost capacitive moisture sensor. Samples of organic composts with distinct waste composition and from different composting stages were used. Machine learning techniques were applied for self-adjustment of the sensor. To validate the model, results obtained in a laboratory by the gravimetric method were used. The proposed model proved to be efficient and reliable in measuring moisture in compost, reaching a correlation coefficient of 0.9939 between the moisture content verified by gravimetric analysis and the prediction obtained by the Sensor Node.

Toxicity and physicochemical parameters of composts including distinct residues from agribusiness and slaughterhouse sludge.

Composting is useful for treatment of residues from agribusiness, but the potential toxicity of the final compost should be evaluated before its agricultural destination. The objective of this study was to evaluate the physicochemical characteristics and the toxicity of agribusiness residues using onion seeds as bioindicators. All tested treatments were composed by sludge from a swine slaughterhouse and sawdust. Besides the control, which included no additional materials, the other treatments included aviary bedding, rice husk and residue from tobacco industries as structuring materials. After 120 days of composting, for all treatments, the temperature inside the composting piles approached the environmental temperature, the physicochemical parameters indicated that the composts were stabilized and, except for the treatment including tobacco residues, that could be used for agriculture without impairing plant germination. Although the treatments including tobacco residues and rice husk showed evidence of cytotoxicity and genotoxicity at the beginning of the composting period, that was not observed for the treatment including aviary bedding. Such potential toxicity was not observed at the end of composting for any of the tested treatments.

Phytotoxicity as an indicator of stability of broiler production residues.

Beddings used for successive broiler lots act as substrate to absorb water and feed from the excreta and may be subsequently used as agricultural fertilizers. This study evaluated the physicochemical characteristics and the phytotoxicity of beddings used to raise five consecutive broiler lots in five aviaries. Samples were collected for beddings not used yet and for beddings used at each of the five broiler lots. Lettuce and cucumber seeds were considered as phytotoxicity bioindicators. As beddings were used for greater number of lots, N, Ca, K, Mg and P contents generally increased, but the C content decreased, the pH alkalinized and humidity was reduced (P < 0.05). The germination index for lettuce and cucumber seeds was reduced with increased bedding (P < 0.05). Beddings used for at least five broiler lots presented decreased C:N ratio and would not recommended for agricultural use due to its toxicity for both tested seeds.

Chemical characteristics of beddings for swine: effects of bedding depths and of addition of inoculums in a pilot-scale.

The effect of depths and of addition of inoculums on the chemical content of swine beddings was evaluated. For beddings 0.25m (25D) and 0.50m (50D) deep, three treatments were tested in two repeats with the same beddings: control (no inoculums); T1 (250g of Bacillus cereus var. toyoii at 8.4×10(7)CFU/g); and T2 (250g of a pool of Bacillus sp. at 8.4×10(7)CFU/g) (250g for 25D and 500g for 50D). For 25D, the C:N ratio was lower, but N, K and C contents were greater than for 50D (P<0.05). The inoculums did not benefit any chemical parameter (P>0.05). In the second repeat, beddings presented lower C:N ratio and greater N, P and K contents than in the first repeat (P<0.05). Thus, the compost produced after using 25D twice had greater fertilizer value than that of 50D.

Addition of Bacillus sp. inoculums in bedding for swine on a pilot scale: effect on microbial population and bedding temperature.

Thermal and microbiological characteristics of beddings for swine were compared according to their depth and of addition of inoculums. Bedding was added to boxes at 0.25 (25D) and 0.50 m (50D), with three treatments: control (no inoculums); T1, with 250 g of Bacillus cereus var. toyoii at 8.4 × 10(7) CFU; and T2, with 250 g of a pool of B. subtilis, Bacillus licheniformis and Bacillus polymyxa at 8.4 × 10(7) CFU (250 g for 25D and 500 g for 50D). Mean temperatures were 28.5 ± 3.9 at the surface and 35.2 ± 8.9 inside the beddings. The most probable number (MPN) of thermophilic bacteria was higher for T1 and T2 than for the control (P<0.05). The MPN of thermophilic bacteria and fungi was greater for D50 than for D25 (P<0.05). The use of 25D without inoculums is recommended due to the reduction of thermophilic microbiota.

Chemical and microbiological characteristics of rice husk bedding having distinct depths and used for growing-finishing swine.

This study compared the effects of different bedding depths on the chemical and microbiological characteristics of the bedding material used to raise pigs during growing and finishing. The experiment was conducted in two pens housing 5 pigs from 60 to 145 days of age, with rice husk beddings 0.50 or 0.25 m deep. Four lots of pigs (replicates) were raised over time in each bedding depth: each bedding was used by two consecutive lots. Bedding samples were collected quarterly to determine the most probable number (MPN) of thermophilic and mesophilic bacteria, fungi and actinomycetes. Contents of N, P, K, C, organic, mineral and dry matter, C:N ratio and pH were also determined. The MPN of thermophilic bacteria was higher for the 0.50 m than for the 0.25 m bedding (p<0.05). The compost of 0.25 m deep bedding had a higher N, P and K content than that from the 0.50 m bedding (p<0.05). Thus, the use of the 0.25 m deep bedding would be recommended due to its greater agronomical value in comparison with the deeper bedding.

Fator do plasma seminal associado à integridade de membrana de espermatozóides suínos pós-descongelamento / Seminal plasma factor associated to post-thawing swine sperm membrane integrity

Neste estudo, identificaram-se polipeptídeos associados à integridade da membrana plasmática (IMP) de espermatozóides suínos após o processo de congelamento/descongelamento. Por meio do perfil protéico do plasma seminal em SDS-PAGE, observou-se a presença de nove bandas polipeptídicas com pesos moleculares que variaram de 11,97 a 122,52kDa. Detectou-se que uma banda de 26,58kDa esteve associada à baixa IMP (<55 por cento). Não foi verificada associação entre as outras bandas e a IMP. Conclui-se que o fator polipeptídico de 26,58kDa está associado à baixa integridade da membrana plasmática do espermatozóide suíno após o congelamento/descongelamento.

Polypeptides associate to membrane integrity (MI) of swine spermatozoa submitted to freezing and thawing were identified. The protein profile of seminal plasma analyzed by SDS-PAGE allowed the identification of nine polypeptide bands with molecular weight ranging from 11.97 to 122.52kDa. One 26.58kDa band was associated with reduced MI (<55 percent). No associations among other bands and MI were observed. The 26.58kDa factor is associated with reduction of membrane integrity of swine spermatozoa after freezing and thawing.

Evaluation of amides and centrifugation temperature in boar semen cryopreservation.

Two experiments were conducted to evaluate the use of amides as cryoprotectants and two centrifugation temperatures (15 or 24 degrees C) in boar semen cryopreservation protocols. Semen was diluted in BTS, cooled centrifuged, added to cooling extenders, followed by the addition of various cryoprotectants. In experiment 1, mean (+/-S.E.M.) sperm motility for 5% dimethylformamide (DMF; 50.6+/-1.9%) and 5% dimethylacetamide (DMA; 53.8+/-1.7%) were superior (P<0.05) to 5% methylformamide (MF; 43.2+/-2.4%) and 3% glycerol (GLY; 38.1+/-2.3%), with no significant difference between MF and GLY. Sperm membrane integrity was higher (P<0.05) for DMA than for MF or GLY (50.9+/-1.9, 43.3+/-2.5, and 34.5+/-2.8%, respectively). Sperm membrane integrity was higher in DMF (47.9+/-2.1%) than in glycerol (34.5+/-2.8%, P<0.05), but was similar to other treatments (P>0.05). In experiment 2, we tested MF, DMF, and DMA at 3, 5, and 7%. Sperm motility and membrane integrity were higher for 5% DMA (53.8+/-1.7 and 50.9+/-1.9%) and 5% DMF (50.6+/-1.9 and 47.9+/-2.1%), in comparison with 7% DMF and all MF concentrations (P<0.05). For sperm motility and membrane integrity, 5% DMA exceeded (P<0.05) 3% DM, with greater membrane integrity than 3% DMF (P<0.05). In both experiments, sperm motility and membrane integrity were superior at 15 degrees C versus 24 degrees C (P<0.05), with no interaction between centrifugation temperature and treatments (P>0.05). In conclusion, boar semen was successfully cryopreserved by replacement of glycerol with amides (especially 5% DMA) and centrifugation at 15 degrees C, with benefits for post-thaw sperm motility and membrane integrity.