Partial characterization of digestive proteases of the three‐spot cichlid Cichlasoma trimaculatum (Günter 1867)

Partial characterization of digestive proteases in the three‐spot cichlid Cichlasoma trimaculatum juveniles was conducted. It was determined that there is higher alkaline proteases activity (3.95 ± 0.32 IU mg^?1 protein) compared to acidic proteases (2.01 ± 0.57 IU mg^?1 protein). Optimal temperature for alkaline proteases is 60 °C which resulted in more thermostability to temperature changes. On the other hand, optimal temperature for acidic proteases is 50 °C. Optimal pH for acidic proteases was pH 2, while for alkaline proteases, it was pH 10, which resulted in more stability in relation to pH changes than acidic protease. The use of specific inhibitors and the SDS‐PAGE electrophoresis analysis revealed seven types of bands for alkaline proteases, which make evident the main presence of serine proteases. In acidic proteases, more than 98 g kg^?1 of the activity was inhibited with pepstatin A inhibitor. Therefore, it is evident that C. trimaculatum digestion is composed by acidic and alkaline proteases; thus, it should be considered an omnivorous fish.     

Productive performance and urinary excretion of mimosine metabolites by hair sheep grazing in a silvopastoral system with high densities of Leucaena leucocephala

The aim of this study was to evaluate daily weight gain (DWG), total dry matter (DM) intake, rumen degradability of forage, and urinary excretion of mimosine metabolites by hair sheep in a silvopastoral system with high densities of Leucaena leucocephala. A completely randomized design was carried out with two treatments: treatment 1 (T1) silvopastoral system with leucaena at a density of 35,000 plants/ha and treatment 2 (T2), leucaena at a density of 55,000 plants/ha. Leucaena was associated with tropical grasses Panicum maximum and Cynodon nlemfluensis. Twenty-four male Pelibuey lambs of 23.2?±?3.4?kg live weight (LW) were used (12 lambs per treatment). Results showed differences (P?<?0.05) in DWG of T1 (106.41?±?11.66?g^?1 sheep^?1) with respect to that of T2 (81.33?±?11.81?g^?1 sheep). Voluntary intake was higher in lambs from T1 (83.81?±?04.07?g DM/kg LW^0.75) with respect to that from T2 (71.67?±?8.12?g DM/kg LW^0.75). There was a difference in color of urine between sheep of T1 and T2, the latter giving positive results for the presence of metabolites derived from mimosine (3-4 dihydroxypyridine and 2-3 dihydroxy pyridone). Rumen degradability of DM of L. leucocephala was higher (P?<?0.05) compared to that of P. maximum and C. nlemfluensis (72.94?±?0.40 vs. 67.06?±?1.50 and 63.25?±?1.51?%, respectively). It is concluded that grazing at high densities of L. leucocephala affects daily weight gain of hair sheep, possibly due to ingestion of high amounts of mimosine which may exert an adverse effect on voluntary intake.     

Development of an Ideotype-Based Selection Tool for Native Tropical Tree Breeding by Smallholder Planters in Mexico’s Maya Forest

Tree planters of the Yucatan peninsula in México are mostly first-generation small-scale forest owners. As a consequence of the lack of a management plan, trees employed for plantations are currently produced without any traceability or genetic improvement protocol, resulting in the reduced quality and heterogeneity of established materials. Recently, the Mexican government published a law to force planters to reverse this situation through the initiation and operation of germplasm management and traceability programs within each physiographic sub-province. Thus, planters located in the “Campeche Karts sub-provenance” now need to select superior trees for plant production, provenance assays, and orchard establishment. As a reference for the improvement goals in this work, we developed a model ideotype tree and qualification tool based on a weight-free selection index to compare trees in established plantations to enable the effective selection of superior trees to be used as seed sources and as a starting population for genetic improvement programs. The tool presented here is easy to use by planters, requiring a very basic computer or smartphone to run a spreadsheet where simple morphometric evaluation are captured, trees are qualified in comparison to the ideotypic values of each parameter with the aid of common field equipment. When this tool was applied to individuals from two different plantations, the qualification methodology ranked the individuals, allowing for the selection of superior trees in a more robust way, in contrast to the use of parameters mostly based on price and driven by wood volume.     

Role of 4-phenyl-3-buten-2-one in boar taint: identification of new compounds related to sensorial descriptors in pig fat.

The possible contribution of other compounds to the development of boar taint in fat samples with low concentrations of skatole and androstenone and classified as tainted was evaluated by GC-MS in the SCAN mode. Skatole and androstenone were determined by normal phase HPLC and GC-MS, respectively. For the identification of other compounds fat samples were purified with a gel filtration column and the second fraction was saponified at room temperature with KOH/3 N MeOH. 4-Phenyl-3-buten-2-one was the main compound identified in the fat samples, and its identification was corroborated by comparison with a standard solution obtained from a commercial source and by HPLC. The sensorial analysis of 4-phenyl-3-buten-2-one showed its possible contribution to boar taint. The possible contribution of phenol derivatives and short-chain fatty acids was also evaluated.     

A three year herd health and management program on thirty Dutch dairy farms. I. Objectives, methods and main results

A herd health and management program was carried out from May 1974 to May 1977 on thirty Dutch dairy farms which did not have specific herd or management problems. The number of cows per farm varied between 40 and 160. There was a control group of thirty-one comparable farms. The farms were visited every six weeks by the veterinarian of the Animal Health Service Institute, the local agricultural adviser of the NAAS and the local veterinarian. The aim of the program was a whole farm approach. The program had a mainly advisory character and it was up to the farmer to follow the advice given, which was based on the theoretically optimal solution but adjusted to the farm situation. The basis of the administration of herd health was the Herd Fertility Chart. Farm inspection was by detailed observation. The program was primarily practical, and could be carried out by a well-trained local veterinarian. The data of the first (preparatory) year were compared with the results of the following two years. The improvement in income feedcosts margin on the program farms exceeded that on control farms by Dfl. 176 per cow (therefore Dfl. 460 per ha. and Dfl. 12,535 per man). Factor Analysis showed that the herd health and management program influenced especially data concerning fertility. However this did not affect the income feedcosts margin per cow. The program also had an important influence on culling due to health problems and on feedcosts per cow, both of which considerably affected the income feedcosts margin per man.(ABSTRACT TRUNCATED AT 250 WORDS)     

Small urban woodlands as biodiversity conservation hot-spot: a multi-taxon approach

To evaluate the importance of urban woodlands to serve as potential sites for biodiversity conservation, we analysed bird, carabid beetle and small mammal community responses to urbanisation at different spatial scales. We analysed the relationships between the variations of the structure (species richness S, diversity H′ and dominance D) of animal communities of woodlands distributed along a rural–urban gradient, and the variations along this same gradient of (1) the vegetation within woodlands, (2) the landscape at 100 m and (3) 600 m around the woodlands. We identified the spatial scales whose variations along the gradient most affected each animal community structure, and characterised community responses to these variations. Our results showed that urbanisation affected taxa differently according to their dispersal ability. Carabid beetles, less mobile, seem to be sensitive to increasing fragmentation and built surfaces from periurban to town centre which could make their movement within the urban landscape difficult. Birds, mobile species, seem to be more sensitive to variations of the vegetation structure within woodlands from periurban to town centre that could affect their capacity to maintain in habitat patches. Although our study did not allow relating the small mammal community structure to urbanisation, it suggests that this taxa is sensitive to urban local disturbances. A relevant management scale of woodlands can be specified for each taxa conservation. Urban woodlands accommodate over 50% of the species present in periurban woodlands, and effective management could enhance this number. Woodlands seem to be a good choice for promoting biodiversity conservation in towns.