Exploring the impacts of different fasting and refeeding regimes on Nile tilapia (Oreochromis niloticus L.): growth performance, histopathological study, and expression levels of some muscle growth-related genes

Abstract

The current study investigated how different fasting and refeeding regimes would impact Nile tilapia growth performance, histopathological examination, and gene expression of myostatin, myogenin, GH, IGF-1, and NPYa. Nile tilapia fish (n = 120) were randomly allocated into four groups, including the control group fed on a basal diet for 6 weeks (F6), group A starved for 1 week and then refed for 5 weeks (S1F5), group B starved for 2 weeks and then refed for 4 weeks (S2F4), while group C starved for 4 weeks and then refed for 2 weeks (S4F2). Fasting provoked a decrease in body weight coincided with more extended starvation periods. Also, it induced muscle and liver histological alterations; the severity was correlated with the length of fasting periods. Gene expression levels of GH, MSTN, MYOG, and NPYa were significantly increased, while IGF1 was markedly depressed in fasted fish compared to the control group. Interestingly, refeeding after well-planned short fasting period (S1F5) modulated the histopathological alterations. To some extent, these changes were restored after refeeding. Restored IGF-I and opposing fasting expression profiles of the genes mentioned above thus recovered weights almost like the control group and achieved satisfactory growth compensation. Conversely, refeeding following more extended fasting periods failed to restore body weight. In conclusion, refeeding after fasting can induce a compensatory response. Still, the restoration capacity is dependent on the length of fasting and refeeding periods through exhibiting differential morphological structure and expressions pattern for muscle and growth-related genes. Graphical abstract

Effects of Prolonged Fasting and Refeeding on Metabolic, Physiological, Tissue, and Growth Performance Adjustments in Colossoma macropomum

“…The prolonged fasting period of 45 days resulted in a general decrease in growth performance, such as the reduction in final length from day 30, as well as the reduction in final weight, weight gain, and specific growth rate after 45 days of fasting. These responses corroborate other studies that also used long fasting periods for other fish species [39][40][41][42]. Furthermore, the 14-day refeeding period promoted greater final weight in the fasted/refed group when compared to the basal group, but this period was not enough for this group to reach the weight, length, and weight gain of the fed group.…”

Coding and Noncoding Genes Involved in Atrophy and Compensatory Muscle Growth in Nile Tilapia

“…For example, complete compensation was reported in some studies, where the starved fish achieved the same weight as the fed fish [ 5 , 12 ]. By contrast, other studies have indicated partial compensatory capacity in Nile tilapia, meaning that feed-restricted fish can increase body weight during refeeding, but cannot reach the weight of continuously fed fish [ 13 , 14 , 15 ]. The physiological processes regulating the compensatory response are not well understood [ 16 ] and can be influenced by the periods of fasting and refeeding, species, age, sex, energy reserves, and environmental factors [ 5 , 7 , 12 ].…”

“…Compensatory growth has been widely observed in many teleost species, including Nile tilapia [ 15 , 17 ], Atlantic salmon [ 18 ], rainbow trout [ 9 ], channel catfish [ 19 ], gibel carp [ 20 ], tongue sole [ 21 ], army fish [ 22 ], European minnow [ 23 ], and barramundi [ 24 ]. However, the molecular mechanisms underlying the exaggerated growth phenotype remain scarce.…”

Sustainability of Growth Performance, Water Quality, and Productivity of Nile Tilapia-Spinach Affected by Feeding and Fasting Regimes in Nutrient Film Technique-Based Aquaponics

“…Generally, factors such as meal type, fish size, fasting length, water quality, and health status have a great impact on the fish's compensatory growth. Prior studies suggested that Nile tilapia had compensatory growth as a result of intermittent fasting and refeeding [21,22].…”