## 1 Introduction
Various studies in animals have investigated the consequences of polyunsaturated fatty acid (PUFA) deficiencies in neurodevelop. Both in vitro and ex vivo studies with cultured mouse neurons have shown that PUFAs play an important role in dendritic growth and the synaptogenesis of neuronal cells [23]. [PERSON] and [PERSON] (2014) [24] have studied the effect of nutritional intervention and its role in inflammatory control. They reported that dietary insufficiency may be a risk factor for ASD. Omega-6 (\(\omega\)-6) PUFAs, such as arachidonic acid (AA) and linoleic acid (LA), have been thought to be proinflammatory, whereas \(\omega\)-3 PUFAs are thought to be anti-inflammatory and/or pro-resolving [25]. Since fish is a significant source of omega-3 fatty acids (n-3 FAs), which are found in the membranes of brain tissue as well [26; 27], studies are exploring their nutritional value as a major preventive for neurodevelopmental disorders. Moreover, fishery products are advised as dietary sources because eating fish is linked to a decreased risk of vascular brain disease [28]. Dietary fish are found to decrease abnormalities in nerve fibres and enlarged fluid-filled spaces around blood vessels in the brain's white matter. Fish eaters are likely to have much lower prevalence of vascular brain disease. Fish is rich in some essential nutrients or minerals, such as selenium, vitamin D, and iodine, which are essential for the growth and development of the brain [29]. According to a recent study on dietary fish intake, fish protein and oil feed can prevent age-related short-term memory loss in mice. The findings also showed that fish feed have physiological advantages for preserving axon shape in the hippocampus and lowering the risk of brain damage [30]. Several studies have demonstrated the role of omega-3 fatty acids in behaviour and reading skills [31; 32]. Almost 30% of kids with autism are put on fish oil supplements. It has been observed that fish oil supplements can reduce hyperactive behaviour in autistic patients [33; 34]. Figure 1 illustrates the involvement of dietary omega-3 fatty acids in various physiological functions related to the development and functioning of the brain and its relationship with a decreased risk of developing various mental disorders, especially autism. The three different types of sea fish (_Lethrinus nebuloses_, _Epinephelus marginatus_, and _Scaridae_), which is widely consumed in the Kingdom of Saudi Arabia, have been used in the present study and were analysed for their fatty-acid profile prior to use. One strategy that could aid in figuring out the process by which autism arises in humans is animal modelling. Presently, we used the PPA-induced rat model of autism. Propionic acid (PPA) has frequently been documented to cause a range of oxidative stresses, altered neurotransmission, impaired energy metabolism, and behavioural abnormalities in rats, which are similar to ASD [35; 36]. This dietary short-chain fatty acid is produced metabolically by enteric bacteria in the stomach and is a common food preservative. Blood-brain barriers (BBB) and the gut-blood barrier (GBB) are both easily crossed by PPA, allowing it to enter the central nervous system (CNS). It can penetrate cell membranes in the brain and build up inside of cells, causing intracellular acidification, which can change neurotransmitter release and, eventually, affect neuronal activity and communication [35; 36]. All these findings motivated us to explore the ameliorative effect of an omega-3-rich fish (_Lethrinus nebuloses_,  
Figure 1: Figure illustrating the involvement of dietary omega-3 fatty acids in various physiological functions related to the development and functioning of the brain and its relationship with a decreased risk of developing various mental disorders, especially autism. Epinephelus marginatus_, and _Scaridae_) diet (whole fish diet as a nutritional intervention) on the neurotoxic effects of propionic acid in a rodent model of autism.