Combination of phytase and citric acid,but not phytase alone,ensures regular rates of growth and bone mineralization in quails under severe phosphorus restriction

An experiment was conducted to evaluate the effects of phytase (PHY), alone or in combination with citric acid (CA), on growing Japanese quails under moderate and severe phosphorus (P) restriction. For this, 504 one‐day‐old female quails were distributed in a completely randomised design with seven treatments and six replications. Treatments consisted of the following diets: (a) positive control (PC): formulated according to quails nutritional requirements; (b) negative control 40% (NC₄₀): PC with 40% less aP; (c) NC₄₀+PHY; (d) NC₄₀+PHY+CA; (e) negative control 65% (NC₆₅): PC with 65% less aP; (f) NC₆₅+PHY; (g) NC₆₅+PHY+CA. Phytase and CA were included at 300 FTU/kg and 40 g/kg, respectively. Performance, bone mineralization and plasma mineral concentration were evaluated at day 35; calcium (Ca) and P metabolism, between days 36 and 39. No significant differences in performance, plasma Ca and P were detected between quails fed PC or NC₄₀; however, NC₄₀ decreased tibia ash (p < 0.01). Treatment NC₆₅ impaired daily weight gain (p = 0.01), tibia ash (p < 0.01), and tibia optical densitometry (p = 0.03), as well as modified plasma Ca (p < 0.01) and P (p = 0.03) concentrations when compared to PC. Both NC₄₀ and NC₆₅ reduced P excretion (p < 0.01). Phytase alone restored tibia ash of NC₄₀ quails to regular rates. Nevertheless, only PHY and CA combined returned plasma P, tibia ash, tibia optical densitometry, and daily weight gain of quails fed NC₆₅ to similar values as those observed in PC. In conclusion, PHY alone suppresses the negative effects of moderate P restriction in growing Japanese quails, but fails in this task under severe P restriction. In such a situation, only the combination of PHY and CA ensures regular rates of growth and bone mineralization. This concept should be better explored by producers in order to take full advantage of the reduction in P excretion achieved by lowering dietary P concentrations.     

Whole-body amino acid pattern of juvenile,preadult, and adult pacu,Piaractus mesopotamicus,with an estimation of its dietary essential amino acid requirements

In the present study, juvenile (live body weight, 54.3 ± 8.2 g), preadult (live body weight, 822.5 ± 33.9 g), and adult (live body weight, 1,562.8 ± 41.8 g) pacu, Piaractus mesopotamicus, were used to estimate their dietary essential amino acid (EAA) requirements using the whole-body amino acid (AA) pattern. The results showed that whole-body moisture, crude protein, total lipid, and ash contents expressed on a wet weight basis (%) were significantly different among the studied growth phases. No significant differences were observed in the dietary EAA requirements estimated for the three growth phases of pacu. These dietary EAA requirements were found to be different than those previously estimated for the same fish through its muscle AA pattern. Based on whole-body EAA to total EAA ratios {A/E ratios; [(each EAA/total EAA) × 1,000]}, EAA requirements were estimated to be histidine (0.42%), arginine (1.36%), threonine (0.82%), valine (0.90%), methionine (0.45%), isoleucine (0.83%), leucine (1.29%), phenylalanine (0.74%), lysine (1.64%), and tryptophan (0.14%) for pacu. These estimated requirements may serve as a reference line in the formulation of practical and experimental diets until dose–response-based optimum EAA requirements are available for pacu.     

Genetic conservation of potentially immunogenic proteins among Brazilian isolates of Babesia bovis

Bovine babesiosis caused by Babesia bovis remains an important constraint for the development of cattle industries worldwide. Effective control can be achieved by vaccination with live attenuated phenotypes of the parasite. However, these vaccines have a number of drawbacks, which justifies the search for better, safer vaccines. In recent years, a number of parasite proteins with immunogenic potential have been discovered. However, there is little information on the genetic conservation of these proteins among different parasite isolates, which hinders their assessment as immunogens. The aim of the present study was to evaluate the conservation of the genes ama-1, acs-1, rap-1, trap, p0 and msa2c among five Brazilian isolates of B. bovis. Through polymerase chain reaction, genetic sequencing and bioinformatics analysis of the genes, a high degree of conservation (98-100%) was found among Brazilian isolates of B. bovis and the T2Bo isolate. Thus, these genes are worth considering as viable candidates to be included in a recombinant cocktail vaccine for cattle babesiosis caused by B. bovis.     

Genetic diversity and changes in phenolic contents and antiradical activity of <Emphasis Type="Italic">Vaccinium myrtillus</Emphasis> berries from its southernmost growing area in Italy

In this study, we evaluated by the RAPD technique the genetic diversity of 42 individual Vaccinium myrtillus L. plant samples, collected from different locations of Tuscan Apennines (Italy), which represent the southernmost growing latitude of this plant. Total polyphenols, total anthocyanins and radical scavenging activity were also determined in two successive harvesting years on bilberry samples obtained from the same individuals characterized by molecular analysis. The RAPD analysis indicated a highly prevalent gamic propagation of bilberry in the investigated area, and, in accordance with genetic findings elsewhere reported for populations of Central and Northern Europe, suggested the presence, from North-to-South Europe, of a clonal-to-gamic genetic gradient of the propagation strategy. In the context of a quite homogeneous panorama of biochemical data, significant variations were occasionally evidenced by comparing closely-located individuals. We tentatively attributed such variations mainly to genetics, due to the very close location of biomes exhibiting different biochemical attributes. However, molecular clustering by RAPD did not show any relationship with biochemical diversity. Strong variations of climatic conditions were probable responsible of the remarkable variability of the investigated biochemical parameters in the two harvesting years.