The effects of dietary protein (DP) levels on the growth, digestibility, digestive enzyme activity and stress tolerance of Litopenaeus vannamei (Boone, 1931) were investigated in high‐density (375 m–3) tank trials. Shrimps (6.2 ± 0.2 g) were fed diets with five different protein levels (31%, 35%, 39%, 43% and 47%) for 60 days. The results showed that variations in DP significantly (P<0.05) influenced the growth performance, digestibility, enzyme activity and their ability to tolerate stress. Weight gain showed a linear increase in relation to crude protein (CP) up to 43% and showed a slight decrease with a further increase to 47%. Feed conversion ratio was observed to be the lowest in CP 43%: 2.53. A higher protein efficiency ratio was observed with the low‐protein diet CP31 (1.07); however, it was not significantly different from the rest of the dietary treatments. Protein digestibility was the highest (75.71%) in CP47 and the lowest (71.94%) in CP31. Protease activity ranged between 63.7 and 70.2 (U Protein–1), and showed a positive correlation with the DP levels. Shrimp fed CP43 well tolerated a sudden decline in salinity and survived for 548.3 min in fresh water. Observations from this study indicate that a DP level around 43% could be optimum for L. vannamei in high‐density culture systems in the absence of natural productivity. 相似文献
Paddy and Water Environment - Increasing crop production is an inevitable demand of a current growing population all over the world. Implementation of best field crop practices potentially enables... 相似文献
A study was conducted to evaluate the effect of feeding different metabolizable energy (ME) and crude protein (CP) levels on performance of Aseel chicken during 0 to 8?weeks of age (Juvenile phase). At 1?day old, 432 chicks were randomly distributed into nine groups. Each group had 48 chicks distributed into eight replicates with six birds in each. Maize-soybean meal-based diets with three ME levels (2,400, 2,600 and 2,800?kcal/kg) and three CP levels (16%, 18% and 20%) were fed to birds in a 3?×?3 factorial design. Different ME levels had significant effect on body weight gain (BWG), feed intake and feed conversion ratio (FCR). Birds fed diet with 2,400?kcal/kg ME had significantly lower BWG (P?相似文献
A comprehensive study was conducted to analyse the meat quality attributes, composition and carcass traits in Aseel chickens and commercial broilers at market age on the basis of physiological age. A total of 20 Aseel (26 and 56 weeks) and 20 broiler (6 weeks) chickens were divided into two groups on a live weight basis, i.e. large (≥2.5 kg) and small (<2.5 kg) with 10 birds in each subgroup.
The pH of meat did not show any significant variation between Aseel and broiler chickens. The meat from heavier birds had significantly higher pH. Shear force value and hydroxyproline contents were significantly higher in Aseel chickens. Aseel birds had significantly higher red (a*) colouration and lower lightness (L*) than broiler chickens.
The texture and acceptability of Aseel meat were significantly higher.
Scanning electron microscopy revealed that muscle fibres in Aseels were arranged in a more coiled pattern making the muscle tough. A larger amount of connective tissue was also observed between the muscle fibres compared with the broiler chickens.
The dressing percentage was significantly higher in larger chickens. Commercial broilers recorded significantly higher meat proportion and lower proportion of bone. The meat:bone ratio was 1.07:1.0 in Aseel and 1.31–1.0 in broiler chicken. Breast muscle content was significantly lower in smaller Aseel chickens. Aseel chicken had stronger and heavier backs and shanks. Abdominal fat percentage was significantly lower in Aseel (0.73–0.78%).
The study concluded that the firm texture of Aseel meat was due to the high collagen content and interlocking connective tissue between the muscle fibres. The texture and acceptability of Aseel meat was higher. Aseel cocks had strong legs, lean meat and less abdominal fat, making them a high-value meat bird in addition to their aggressive fighting ability.
An attempt was made to determine the replication efficiency of hepatopancreatic parvo‐like virus (HPV) of shrimp in different organs of freshwater rice‐field crab Paratelphusa hydrodomous (Herbst) using bioassay, PCR, RT‐PCR, ELISA, Western blot and q‐PCR analyses. Another attempt was made to use this crab as an alternative to penaeid shrimp for the large‐scale production of HPV. This crab was found to be highly susceptible to HPV by intramuscular injection. The systemic HPV infection was confirmed by PCR and Western blot analyses in freshwater crab. The expression of capsid protein gene in different organs of infected crab was revealed by RT‐PCR analysis. Indirect ELISA was used to quantify the capsid protein in different organs of the crab. The copy number of HPV in different organs of the infected crab was quantified by q‐PCR. The results revealed a steady decrease in CT values in different organs of the infected crab during the course of infection. The viral inoculum that was prepared from different organs of the infected crab caused significant mortality in post‐larvae of tiger prawn, Penaeus monodon (Fabricius). The results revealed that this rice‐field crab could be used as an alternative host for HPV replication and also for large‐scale production of HPV. 相似文献
Downy mildew of sorghum (DMS) has serious implications agronomically worldwide and to-date the search for a potent fungicide is a high priority and necessity. Phytochemicals have proven to be effective against various plant pathogens with minimal or no side effects. Duranta repens aqueous extract exhibited a promising potential as an organic fungicide for management of sorghum downy mildew (Peronosclerospora sorghi) in greenhouse conditions, at low concentration of 5 %. Activity guided bio-prospecting lead to the isolation of active principle which could control the DMS at as low as 0.1 % concentration. Spectral studies identified the bioactive contributor as a phytosterol namely 16-Hydroxy-8,10,13-trimethyl-1,2,8,10,12,13,14,15-octahydro cyclopenta [a] phenanthren-3-one, designated as Durantol. The results of microscopy exhibited the inhibition of conidial germ-tube growth by formation of bulb-like swellings at the tip, suggesting the mechanism of action of Durantol was via hampering the membrane integrity of the pathogen. Further, the same was virtually predicted using molecular docking for structure-activity relationship (SAR) against four best known membrane receptors namely 1-UDP-glycosyltransferases (UGT), cytochromes P450 (P450), oxidosqualene cyclase (OSC) and serine carboxypeptidase-like acyltransferase (SCPL), proposing that glycosylation onto the membrane would be a reason for inhibition and which is evident from atomic contact energy (ACE) values. The results of the study indicate that, organic management of airborne inoculum of downy mildew of sorghum is feasible and preferable, as compared to the use of chemical fungicides, considering human and environmental health concerns.
In the present experiment, the expression profile of Toll-like receptor mRNA in indigenous and pure line chickens was studied.
The expression of TLR3, TLR4, TLR5 and TLR7 were quantified in heterophils of Aseel, Kadaknath, Naked neck, Dwarf and White
Leghorn lines by Quantitative Real-time PCR. White Leghorns expressed significantly (P < 0.01) higher levels of TLR3 mRNA
compared to other lines. TLR4 and TLR5 mRNA were significantly highly expressed in Kadaknath line. Among the TLRs investigated
TLR5 was more expressed in all lines studied. TLR7 was highly expressed in indigenous chicken Aseel and Kadaknath than other
lines. Dwarf chicken expressed significantly (P < 0.01) lower levels of all TLRs investigated. On the basis of the present
study we conclude that the differential expression of TLR mRNA in the heterophils of indigenous and other chicken breeds might
contribute to their variable disease resistance/susceptibility. 相似文献
Tropical Animal Health and Production - Variance and genetic parameters were estimated for growth and production traits of synthetic broiler female line (PB-2) using REML animal model to delineate... 相似文献
