RESPONSE OF RICE (ORYZA SATIVA L.) UNDER ELEVATED TEMPERATURE AT EARLY GROWTH STAGE: PHYSIOLOGICAL MARKERS

A reliable and rapid assessment technique, for evaluation of cultivars having potential to combat harsh environmental conditions is imperative. This experiment was carried out to screen 8 local (Pakistan) accessions of rice at early growth stage (germination and seedling) at control and heat shock for different time periods (24, 48, 72 h). Heat stress indices, including promptness index (P.I.) and germination stress index (G.S.I.), were used to explore thermotolerance at germination stage. At seedling stage, relative membrane permeability (RMP) were assessed through measurement of electrolyte leakage (EC), melondialdehyde (MDA) and production of hydrogen peroxide. It is observed that heat stress delayed germination and decreased germination percentage at germination stage. However cultivars showed significantly different response. Among all, "Kanwal-95" showed more thermotolerance in terms of maximum number of germination as well as in speediness to germination. Physiological indicators manifested, increased electrolyte leakage is associated with increased level of lipid peroxidation and hydrogen peroxide. It can be concluded that antioxidants enzymes could play major role in thermotolerance by scavenging free radicals to protect lipid peroxidation consequently improve cell membrane thermostability. Results analysis revealed that these indicators were simple and accurate selection criteria to assess heat stress effect and can be adopted to save resources and time of formers

Effect of natural growth promoters on immunity, and biochemical and haematological parameters of broiler chickens

Purpose: To investigate the efficacy of promising alternatives to antibiotic growth promoters (organic acids, phytobiotics, and their combinations) as feed additives in poultry feed.Methods: Different feed treatments were formulated with organic acids, phytobiotics and their combinations, and their effects on blood profile, serum enzymes and immunity parameters were evaluated in broilers at 21 and 42 days of age.Results: Cholesterol, triglyceride and HDL levels of the 21- and 42-day old broilers were significantly (p < 0.05) affected by the feed additives. The effect of albumin and albumin/globulin ratios varied significantly (p < 0.05) from that of the control group at 42 days of age. Haematological analysis did not show significant changes (p > 0.05) in parameters except hematocrit, RBC, MCH, MCHC, WBC at age 21 days. However, among the serum enzymes assayed, only gamma-glutamyl transferase activity was altered for the modified feed group.Conclusion: These results suggest that supplementation with organic acids and phytobiotics can be used as alternatives to antibiotic growth promoters without interfering with the overall health and performance of broilers.Keywords: Broilers, Antibiotic growth promoters, Phytobiotics, Organic acids, Biochemical parameter

Comparative Biochemical Analysis of High and Low Sucrose Accumulating Sugarcane Varieties at Formative Stage under Heat Stress

Sugarcane (Saccharum officinarum L) is a valuable cash crop which plays an imperative role in the worldwide economy. However, high temperature has significantly retarded the crop growth and yield by alteration of biochemical pathways. Therefore, the biochemical activities of two sugarcane varieties were explored under heat stress condition. The sugarcane cultivars S2003-US-633 (high sucrose accumulation) and SPF-238 (low sucrose accumulation) were cultivated and subjected to different temperature regimes i.e. control at 30±2 °C, heat stress at 45±2 °C and recovery at 30±2 °C for 24, 48 and 72 hours at formative stage. Detailed profiling of physiochemical attributes, sugar analysis linked with sucrose metabolism enzymes and thermotolerance indicators were investigated. S2003-US-633 exhibited better response in terms of sugar accumulation regulated by sucrose synthase, sucrose phosphate synthase and invertase activities along with more proline accumulation, total soluble protein contents with response to high temperature exposure. While S2003-US-633 is ranked as tolerant variety due to less MDA, H2O2 content and electrolytes leakage exhibiting its efficient tolerance mechanism, giving high sugar recovery rate despite harsh environmental conditions. Thus, these findings can be helpful in providing information for engineering sugar improvement along with thermotolerance in sugarcane varieties and providing new avenues towards the economic development of the country