Elevated temperature affects growth and hemato‐biochemical parameters, inducing morphological abnormalities of erythrocytes in Nile tilapiaOreochromis niloticus

Abstract

Temperature is considered as an important environmental factor, and the increasing water temperature resulting from global warming is a great concern. The present study was conducted to examine the effects of elevated water temperature on growth, hemato‐biochemical parameters in Nile tilapia, Oreochromis niloticus acclimatized to three temperatures (31°C, 34°C and 37°C) for 60 days. Additionally, erythrocytic cellular abnormalities (ECA) and erythrocytic nuclear abnormalities (ENA) tests were assayed using peripheral erythrocytes after exposure to the three temperatures. Fish were sacrificed on days 7, 15, 30 and 60 of exposure. Growth performances viz., weight gain, % weight gain and specific growth rate (SGR) showed decreasing tendency at 34°C but significantly declined at 37°C compared to 31°C. The abundance of haemoglobin (Hb) and red blood cells (RBCs) significantly decreased in response to temperature increases, while white blood cells (WBCs) displayed the opposite response. At days 7 and 15, blood glucose levels significantly increased in response to the temperature increase, while at days 30 and 60 glucose declined. Frequencies of ECA and ENA were significantly enhanced at the highest temperature throughout the experimental period. Dissolved oxygen decreased and free CO2 increased significantly with increasing temperature throughout the study period. The present study revealed that temperatures higher than 34°C may be hazardous to O. niloticus.

Tilapia Farming in Bangladesh: Adaptation to Climate Change

“…The balanced sex ratio of O. niloticus does not deviate significantly even up to 36 • C [92]. A study on the haemato-biochemical parameters also revealed that temperatures up to 34 • C may not be hazardous for Nile tilapia [96]. A comparative study suggests that embryonic development and hatching of carp are significantly affected even at 33 • C [112].…”

“…Table 2 summarizes the effects of temperature changes on the physiological alterations of tilapia. The thermal effects on tilapia showed that growth performance significantly decreased after at 34 • C, although this showed a decreasing tendency towards high temperature changes [91][92][93][94][95][96]. Before they reached 5 days old tilapia (O. mossambicus) showed significantly increased percentages of deformity, and a greater number of males was induced by high temperature (28 and 32 • C) after 10 days [97].…”

“…Non-specific immunity (lysozyme activity) of Nile tilapia can significantly decrease due to high temperature (33 • C) [99]. Recently, Islam et al [96] found variable effects of high temperature (37 • C) on the hemato-biochemical parameters of tilapia. Here, the abundance of hemoglobin and red blood cells were significantly reduced, although the amount of white blood cells and blood glucose were increased.…”

“…The ultimate upper lethal temperature for T. mossambica lies at 38 • C [107]. Recent studies showed that tilapia can tolerate temperatures of up to 34 • C without any significant effect on their growth rate [94,96]. In addition, the cortisol level, which is the stress indicator in tilapia, does not significantly increase even at 36 • C [108], which suggests that tilapia can tolerate high temperatures, whereas for L. rohita, another commonly cultured species in Bangladesh, a temperature of 36 • C may be hazardous for growth and can cause physiological damage [109][110][111].…”

New Insights Into Hematological, Serum Biochemical and Histopathological Toxicity of Bisphenol a on Bighead Carp (Aristichthys Nobils) Under Long-Term Exposure

“…Islam et al, 2019) while hematocrit %, hemoglobin quantity and total proteins were measured according to earlier protocols(Hussain et al., 2019; Ghaffar et al 2020) at days 15, 30, 45 and 60 of the experiment. Serum biochemical studies For different serological parameters, serum was separated from the blood of each sh placing on ice at different experimental intervals at days 15, 30, 45 and 60 of the experiment.…”