Nitrogen nutrition of guava trees in response to byproduct of fruit processing

Studies of the effect of organic fertilization of perennial crops are scarce due to the time necessary for the plants to present the first results. The objective of this study was to assess the leaf nitrogen (N) content, the direct and indirect measures of chlorophyll content, fruit yield and their correlations in an orchard of adult guava trees of the Paluma cultivar, through five consecutive harvests, in function of application of a byproduct of guava processing. The following doses of the byproduct were applied: 0, 9, 18, 27 and 36 t ha^?1. The material was applied on the surface, without incorporation, once a year between 2006 and 2010. The byproduct doses influenced the nitrogen concentrations, SPAD index, chlorophyll b level and fruit production.     

Estimated Reduction in Solids During Sheep Bedding Composting as a Function of the Composition of the Organic Fractions

The different organic matter fractions of residues significantly impact the degradability of organic material in composting windrows. Based on that, this study aimed to find out the organic matter fractions that most impact the breakdown rate during composting, besides proposing models to estimate the solids reductions in sheep bedding composting windrows. To that end, 24 sheep beddings from different locations and varied composition were composted so as to ensure the representativeness of the sample. The models found for reduction in total (TS) and volatile (VS) solids as a function of compostable organic matter (COM) and organic matter resistant to composting (OMRC) were not significant. Lignin had correlation coefficients of ?0.6, ?0.89, and ?0.84 in relation to temperature, TS reduction, and VS reduction, respectively. The hemicellulose:lignin ratio was the parameter most correlated with temperature (0.69), TS reduction (0.91), VS reduction (0.92), and nitrogen (0.5), which led to more significant predictive models. It can be concluded that the hemicellulose:lignin ratio is the parameter that most impacts the breakdown of organic matter and nitrogen losses in sheep bedding composting windrows.     

Genome-wide scan for runs of homozygosity in the composite Montana Tropical® beef cattle

The aim of this study was to assess the distribution of runs of homozygosity (ROH) and autozygosity islands in the composite Montana Tropical^® beef cattle to explore hotspot regions which could better characterize the different biological types within the composite breed. Montana animals (n = 1,436) were genotyped with the GGP-LD BeadChip (~30,000 markers). ROH was identified in every individual using the plink v1.90 software. Medium and long ROH prevailed in the genome, which accounted for approximately 74% of all ROH detected. On an average, 2.0% of the genome was within ROH, agreeing with the pedigree-based inbreeding coefficient. The Montana cattle with a higher proportion of productive breed types showed the highest number of autozygosity islands (n = 17), followed by those with a higher proportion of breeds adapted to tropical environments (n = 15). Enriched terms (p < .05) associated with the immune and inflammatory response, homeostasis, reproduction, mineral absorption, and lipid metabolism were described within the autozygosity islands. In this regard, over-represented GO terms and KEGG pathways described in this population may play a key role in providing information to explore the genetic and biological mechanisms together with the genomic regions underlying each biological type that favoured their optimal performance ability in tropical and subtropical regions.     

Natriuretic peptide system regulation in granulosa cells during follicle deviation and ovulation in cattle

Natriuretic peptides (NPs) are known to regulate reproductive events in polyovulatory species, but their function and regulation in monovulatory species remain to be fully characterized. Using a well‐established in vivo model, we found that bovine granulosa cells from follicles near the deviation stage express mRNA for the three NP receptors (NPR1, NPR2 and NPR3), but not for NP precursors (NPPA, NPPB and NPPC). The abundance of NPR3 mRNA was higher in dominant compared to subordinate follicles at the expected time of follicular deviation. After deviation, mRNA for all NP receptors was significantly more abundant in the dominant follicle. Intrafollicular inhibition of oestrogen receptors downregulated NPR1 mRNA in dominant follicles. In granulosa cells from preovulatory follicles, NPPC mRNA increased at 3 and 6 h after systemic GnRH treatment, but decreased at 12 and 24 h to similar levels observed in samples collected at 0 h. After GnRH treatment, NPR1 mRNA was upregulated at 24 h, NPR3 mRNA gradually decreased after 3 h, while NPR2 mRNA was not regulated. The mRNA expression of the enzyme FURIN increased at 24 h after GnRH treatment. These findings revealed that the expression of mRNA encoding important components of the NP system is regulated in bovine granulosa cells during follicular deviation and in response to GnRH treatment, which suggests a role of NP system in the modulation of these processes in monovulatory species.     

Gender status effect on carcass and meat quality traits of feedlot Angus × Nellore cattle

The study evaluated the effect of gender status on carcass and meat quality of feedlot Angus × Nellore cattle. A total of 176 cattle, 20 months old, were confined for 190‐days and assigned to four treatments: bulls, immunocastrated, steers, and heifers. Bulls had greater rib eye area and HCW (p = 0.0001). Heifers had increased fat thickness (p = 0.0001). Steers and heifers had higher marbling scores (p = 0.0001). There was interaction between gender and aging time for Warner‐Bratzler Shear Force (p = 0.0002), L* (p = 0.0118), and b* (p = 0.0113) values of beef. The sensory panel results showed that beef from bulls had the lowest consumer overall acceptance (p = 0.0278). Especially, regardless tenderness, steers and immunocastrated beef were considered tender, independent of aging time. Beef produced by heifers, steers, and immunocastrated is considered to be of higher quality than bulls. Thus, it is may be an interesting alternative to produce high‐quality beef than bulls, to attend the consumer demand for high‐quality products. Additionally, the low fatty acids n6 levels and low n6:n3 ratio, high levels of CLA, MUFAs, and oleic acid suggests that the heifer meat is favorable for human health.