High environmental temperature is perhaps the most important inhibiting factor to poultry production in hot regions. The objective of this study was to test adaptive responses of chickens to high ambient temperatures and identify suitable indicators for selection of heat-tolerant individuals. Full-sib or half-sib Anak-40 pullets (n = 55) with similar body weights were raised in a room with a temperature ranging from 24°C to 28°C, and relative humidity of 50% from 61 to 65 days of age. On day 66, the ambient temperature was increased within 60 min to 35 ± 1°C which was defined as the initial of heat stress (0 h). Rectal temperature (RT) was measured on each pullet at 0, 6, 18, 30, 42, 54 and 66 h. After 66 h the ambient temperature was increased within 30 min to 41 ± 1°C and survival time (HSST) as well as lethal rectal temperatures (LRT) were recorded for each individual. The gap between the RT and initial RT was calculated as ΔTn (ΔT6, ΔT18, ΔT30, ΔT42, ΔT54 and ΔT66), and the interval between LRT and initial RT as ΔTT, respectively. A negative correlation was found between HSST and ΔTn as well as ΔTT (rΔ T 18  = -0.28 and rΔ TT  = -0.31, respectively, P < 0.05; rΔT30  = -0.36, rΔ T 42  = -0.38, rΔT54  = -0.56, P < 0.01). Importantly, pullets with low ΔT18 showed a longer HSST (256.0 ± 208.4 min) than those with high ΔT18 (HSST = 123.7 ± 78.3 min). This observation suggested that the ΔT18 or early increment of RT under heat stress might be considered as a reliable indicator for evaluation of heat resistance in chickens.

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Indigenous chickens from various part of China, due to different feather characters, always performed differently when countered with cold stress. In this study, the effects of long term hypothermia on serum hormones (triiodothyronine, thyroxine and insulin) and activity of plasma enzymes (Alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase, creatine kinase and lactic dehydrogenase) were studied in two indigenous broiler breeds, Huainan partridge (H) and Wenchang (W) chickens. Chickens in 20°C±2°C were compared with those subjected to moderate (15°C±2°C) and severe low temperature (10°C±2°C) for one week. Long-term hypothermia elevated plasma insulin and reduced T4 in W, decelerated insulin and increased T4 in H, while T3 did not change in the two breeds. Plasma enzymes AST, LDH and CK decreased in the two breeds and ALT only decreased in W exposed to cold stress. A significantly decreased body weight gain of H and no variations in W at low temperature were observed. However, a trend of decreased weight gain in W was observed when bred under low temperature condition. Follicle density and diameter were compared in the two breeds with back density in H significantly higher than W and diameter from back of H significantly smaller than W, while much larger than the latter at latero-abdominal part. We investigated the pattern of serum biological change, follicle diameter and density under cold stress condition in two indigenous broiler breeds from different areas of China to provide informative guidance for broiler production and indications in breeding of cold resistant breed.

It is clear that heat shock protein 70 (HSP70) is responsible for stressful conditions. However, the expression level and profile of HSP70 during cold stress are still unknown. In this study, the expression profile of HSP70 in the heart, liver, muscle and spleen of Huainan partridge chicken exposed to low temperature was investigated. HSP70 expression was showed tissue-dependent with highest expression in muscle, followed by liver and heart; conversely, there was no evidence of changes in spleen, where there were two expression peaks during cold stress, before 3 and after 72 h, respectively. The plasma creatine kinase (CK) activity exhibited a significant increase (P<0.01) after 1 h of cold stress exposure, and then decreased till to the lowest level after 72 h of cold stress exposure. On the other hand, nitric oxide content arose and reached the peak level (P<0.01) after 3 h of cold stress exposure, and then suddenly decreased to the original level with the duration of exposure time. In conclusion, mRNA expression of HSP70 turned out to be tissueand time-dependent in muscle, liver and heart in broilers under cold stress exposure. The distinct expression of HSP70 suggested that highenergy supply and balance of CK activity might be responsible for the HSP70 high expression.

To strengthen the COD removal from actual coking wastewater, a lab-scale granular bio-film reactor was continuously operated at three stages for about 9 months: anaerobic vs. micro-aerobic (over 2 months), with and without supplement of bicarbonate (over 2 months), and with and without supplement of diatomite (about 4 months).Compared with anaerobic condition, the micro-aerobic operation could strengthen COD removal in the actual coking wastewater and increase COD removal efficiency from 21.4% to 36.4%. At micro-aerobic operation conditions, the supplement of 3g.Linfluent-1 bicarbonate could distinctly increase COD average removal efficiency from 32.9% to 65.3%, and the supplement of 6g·L-1·d-1 diatomite could significantly increase COD average removal efficiency from 33.1% to 78.1%. The supplement of bicarbonate or diatomite for the granular bio-film reactor must be an effective way for the treatment of actual coking wastewater.