Fish By-Products Consumption and Discard Pattern in Nigeria

Significant portions of by-products are generated and discarded throughout the fish supply chain. To reduce the discard of these by-products and ensure their proper utilization, there is a need to ascertain its discard and consumption pattern among fish consumers. The main aim of this study was to investigate the by-products fish consumers in Lagos State, Nigeria regard as waste; discard and consume. Factors which influence the discard and consumption of these by-products were also investigated. Using a Multistage sampling procedure, a structured questionnaire was used to obtain information from 300 respondents in three Local Government Areas (LGAs) in Lagos State, Nigeria and the data collected were analyzed using descriptive and inferential statistics. The results show that the scales (92%) were the most discarded by-product followed by gut (89%), gills and fins (85%). The skin was the most consumed by-product while the gut was the least consumed. The three major reasons given by the respondents for the discard of these by-products were that they considered them uneatable, useless and a waste. Several interrelating factors, such as social factors, type of fish species and socio-demographic characteristics also influenced the by-products respondents in this study regard as waste; discard and consume. The results in this study indicated that the scales, gut, gills, and fins were largely discarded and underutilized by fish consumers in Lagos State, Nigeria. There is a need for research on sustainable ways to recover and utilize discarded by-products for the development of value-added products and for the realization of a sustainable circular economy

Storage fungi and mycotoxins associated with stored smoked Catfish (Clarias gariepinus)

Studies were carried out to determine the occurrence of storage fungi and their respective mycotoxin in stored smoked dried fishes. A total of 45 fishes were bought fresh, smoked and stored under three different storage conditions (an air tight container, a bamboo basket and an iron basket). Using the pour plate method, isolation and identification of storage fungi were carried out weekly for four consecutive weeks from each storage container. Mycotoxin detection and quantification were also carried out on each stored smoked fish samples using Agra-Quant kit. The proximate analysis of the stored fish samples prior to storage, and after storage from each storage container was also analysed. Results revealed five fungal isolates associated with the stored samples namely: Aspergillus flavus, A. fumigatus, A. niger, A. wentii and Penicillium species. Four species of Aspergillus and one Penicillium species were isolated and identified from two of three storage condition used (bamboo basket and iron basket) from third week of storage. It was deduced from the mycotoxins analysis results that Aflatoxin B1 and Ochratoxin were present in the stored smoked samples of the two above mentioned storage containers. Results from the proximate compositions revealed a decrease in the ash content, crude fiber and crude protein as the storage period increases. Fat and moisture content of the stored fish samples were observed to increases weekly throughout the storage period in bamboo basket and an iron basket. In conclusion, it can be deduced that storage container play a vital role in the preservation/shelf -life of smoked dried fish

Chemical, Sensory and Microbiological Changes of Spotted Grunter (Pomadasys commersonnii) Under Ice Storage

The effects of two types of ice on the quality of Pomadasys commersonnii with storage time were conducted. The overall sensory evaluation otherwise known as quality index (QI) ranged from 3 – 0, the scores of 3 was for very fresh fish while zero implied deterioration. The QI for fish stored in ice block ranged from 2.9 – 1.0, 2.0 – 0.0, 2.2 – 0.0, 3.0 – 0.0, 2.8 – 0.2 and 3.0 – 1.0 for skin, gill, belly, odour, eyes and colour, respectively and for fish samples stored in ice cube were 2.9-1.0, 2.5 -0.0, 2.2-0.0, 2.9-0.0, 2.2-0.0 and 3.0-1.0 for skin, gill, belly, odour, eyes and colour respectively from the 4th to the 22nd day. The QI of the fish stored in ice block at 18th day which is the shelf life were 1.6, 1.4, 1.2, 1.1, 1.4 and 2.0 while that of fish samples stored in cube ice were 1.6, 1.3, 1.0, 0.6, 1.5 and 2.0 for texture of skin, gill, belly, odour, eyes and colour along vertebra column. The odour was fresh until after the 8 days; the belly/ gut has the least QI scores and this corresponded with the microbial load that has the highest count. The shelflife of the fish species was estimated to be 18 days. At this time, the fish was still acceptable by the panel members. The microbial load of the skin, flesh, gut and gill at day zero was less than 0.5 x 102 and 8.5 x 102 -1.56x105, 5.5 x102- 1.25x107, 8.5x102-3.78 x107 and1.3x102 - 1.89 x107 cfu/g and 1.22 x105, 1.82 x105, 2.48 x107 and 2.22 x 107 cfu/g, respectively for samples stored in block and cube ice. Trimethylamine for fish samples stored in block ice ranged from 0.6 -15.1 mg/100g while that of cube ice was from 0.6 to 16.3 mg/100g. Total volatile nitrogen ranged from19.5- 42.1 mg/100g and 19.5 - 43.7 mg/100g for samples stored in block and cube ice, respectively. The pH increased steadily throughout storage from an initial pH of 7.0 to 7.48 and 7.56 for block and cube ice, respectively. Moisture and protein range for samples stored in block ice were 81.3-80.6%, and 19.5-17.02% while for samples stored in cube ice were 81.3- 83.9% and19.5-15.5%, respectively. Ash remained constant at 1% for all the samples. Results showed a non-significant difference (p = 0.05), which is an indication that they have the same storage or preservative capacity.Keywords: Ice, grunter, sensory, microbiological, proximat

Food and Feeding Habits of the Guppy, Poecilia reticulata, from Drainage Canal Systems in Lagos, Southwestern Nigeria

The food and feeding habits of the Guppy, Poecilia reticulata, from drainage canal systems in Lagos Metropolis, Nigeria, was investigated over a period of 24 months. Fish samples were collected monthly from 15 study sites. A total of 2400 fish stomachs were analyzed using the numerical and frequency of occurrence methods. P. reticulata fed mainly on algae, organic detritus, diatoms, mosquito larvae parts, protozoan, zooplankton and fish parts while algae form the most abundant and important food item, constituting 79.03% of food items by numerical and 33.17% by occurrence of stomachs examined. Amongst the algae, Ulothrix sp. was the most preferred, constituting 33.17% by numerical and 20.82% by occurrence. The least eaten food item was fish parts constituting 4.46% by numerical and 1.19% by occurrence. There was a significant difference (P < 0.05) in the number of algae and mosquito larvae consumed, while there was no significant difference (P > 0.05) in the number of other food items consumed for both seasons. However, by occurrence method there was no significant difference (P > 0.05) in food items consumed for both seasons. The three size classes of P. reticulata exhibited similar food habits with the presence of eight categories of food items in their stomachs. The largest size class ate more of algae, organic detritus and fish parts, followed by the medium size class while the small size class ate less of these food items. The species is an opportunistic benthopelagic omnivores, whose preference for food fluctuates with season, with a peak in diversity of food types occurring in the rainy season

Quality assessment of smoke-dried Clarias gariepinus and Chrysichthys nigrodigitatus stored in two storage facilities

The quality of smoke-dried fish can be enhanced by storing the products in good storage facilities. This research was carried out to determine the proximate composition, microbiological quality and sensory properties of smoke-dried Clarias gariepinus and Chrysichthysis nigrodigitatus stored in refrigerator and kitchen cabinet during a 6-week storage period. Sensory properties were assessed using panel of assessors. Bacterial load was done using plate count agar spread plate technique. Fish were purchased alive, washed, sacrificed and smoked for 72 hours. Percentage weight loss after smoking C. gariepinus and C. nigrodigitatus were 57.42% and 65.91%, respectively. Results for crude protein, moisture and lipid content of smoke-dried C. gariepinus stored in refrigerator ranged between 67.80-68.31%, 8.32-9.00% and 12.15-12.34% while the values for those stored in kitchen cabinet ranged from 67.04-68.30%, 8.30-8.49% and 12.15-12.34, respectively; for smoke-dried C. nigrodigitatus the ranges of the nutrients were 61.75-62.20%, 7.40%-8.00, 16.15-16.28% and 60.89-62.19%, 7.40-7.49%, 16.15-16.28% for those stored in refrigerator and kitchen cabinet, respectively. The results showed no significant difference (p>0.05) in proximate composition of the samples in the two storage facilities. Microbes isolated from the smoke-dried fish samples were Staphyloccus aureus, Bacillus subtilis and Escherichia coli. Total bacterial counts (TBC) at week 6 for C. gariepinus were 0.17×10-6 and 0.25×10-6; C. nigrodigitatus, 0.24×10-6 and 0.31×10-6 in refrigerator and kitchen cabinet, respectively, and the values were not significantly different (p>0.05) in the two storage facilities. No fungal growth was present throughout the six-week storage period. The sensory quality ratings ranged between 8.00±0.00 for flavour and 4.67±0.58 for overall acceptability. Sensory quality was significantly different (p<0.05) in flavour, texture, appearance and aroma at week 2 and 6. The findings of this study show that the storage facilities retained good nutritional and sensory qualities as well as overall acceptability of the smoke-dried fish throughout storage

An Automated Combined Microwave and Electric-Element Fish Dryer

This work provides an improvement in the efficiency and economics of the drying process by combining an electric hot air flow and microwave drying unit. It is intended to improve the nutritional qualities for the dried fish market and its shelf life. We fabricated a drying Kiln having combined 1.6KW twin microwave gun and 4KW quad electric element, volume 897,000cm3 and wet fish cargo capacity up to 80Kg. The characteristics of electric drying (ED) and combined microwave-electric drying (MED) of Clarias Gariepinus tissues were studied experimentally. Results show that the moisture ratio decreases with an increase in microwave drying time when microwave power is fixed. The drying rate is fast initially and then falls slowly. Finally, the curve of MED was steeper than that of ED alone during the initial drying period. The data of the percentage of water and volatile oil loss by drying with respect to time follows a logarithmic relationship. The taste panels evaluations and sample results of organoleptic assessment of the dried Clarias Gariepinus was found to range from excellent quality for appearance, taste and odour, good quality for fragmentation and texture. The addition of microwave to the electric heater has saved about 28 hours in drying time and reduced the product cost by energy consumption to 38%. In conclusion this method provides rapid dehydration (shorter drying time), improved product quality and flexibility in drying a wide variety of product

Effects of smoking on fatty acids composition of croaker (Pseudotolithus senegalensis)

Fish meat has become a component of a healthy diet, as it is considered a source of essential fatty acids. The effects of smoking on the fatty acids composition (FAC) of smoked croakers were determined. Smoked croakers were produced using improved smoking kiln by Nigerian Institute for Oceanography and Marine Research. The smoked croakers were packed in polythene bags and transported to Matis Research Laboratory, Iceland for analysis. The FAC were 91.44% of lipid and 91.51% of lipid for fresh and smoked croakers respectively. There was no significant difference (P>0.05) in the FAC as a result of smoking. However, the saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) increased significantly (P<0.05) with significant (P<0.05) reduction in polyunsaturated fatty acids (PUFA) as a result of smoking. There was also significant (P<0.05) reduction in the FAC of the smoked croakers analysed with skin to that of smoked croakers analysed without skin (skinless).The relationship of PUFA to SFA for fresh and smoked croakers were greater than 0.4 and the omega-6 to omega-3 ratios of both the fresh and smoked croaker were far less than one (1) thus constituting an excellent source of omega-3 fatty acids and a highly healthy food.Keywords: Croakers, smoked, fatty acids composition, with skin, skinles

The role of humanities in the medical curriculum: medical students' perspectives

Background The humanities have long been shown to play an important role in the medical school curriculum. However, few studies have looked into the opinions of medical students on the usefulness and necessity of the humanities as well as their extracurricular involvement with them. The aim of this study was to: a) understand medical students’ attitude towards the humanities in medical education and b) assess their understanding of the necessary qualities of doctors and how interaction with the humanities affects the development of such attributes. Methods A mixed methods survey was designed to elicit demographics, engagement, interest and perspective on curricular positioning, and to explore how students ranked the qualities of a doctor. It was distributed to medical students of all year groups in the 6-year bachelor of medicine, bachelor of surgery (MBBS) course at Imperial College London. Results 109 fully completed questionnaires were received. No significant difference was found in engagement or interest in the humanities between genders. Students felt strongly that humanities subjects shouldn’t be assessed (71:18) though some felt it was necessary for engagement, while no consensus was reached on whether these subjects should be elective or not (38:31). The majority of students wanted more medical humanities to be incorporated into the traditional medical course with a preference of incorporation into the first 3 years. Junior medical students were more likely to rank empathy as a highly desirable attribute than senior students. Students provided qualitative insights into curricular positioning, assessment and value. Conclusions This study provides the perspective of medical students on how and whether the humanities should be positioned in medical education. It may be helpful to medical schools that are committed to student involvement in curriculum design

Lighting in the home and health: a systematic review

Poor housing is an important determinant of poor health. One key aspect of housing quality is lighting. Light is important for visual performance and safety, and also plays a vital role in regulating human physiological functions. This review aims to synthesise existing evidence on the relationship between lighting in the home and health and recommends areas for future research. Three databases were searched for relevant literature using pre-defined inclusion criteria. Study quality was assessed using the Newcastle Ottawa Scale. Extracted data were qualitatively synthesised according to type of lighting (natural light, artificial light and light at night) and stratified by broad health domains (physical, mental and sleep health). Of the 4043 records retrieved, 28 studies met the inclusion criteria. There was considerable heterogeneity in light exposure metrics used and specific health outcome assessed by the studies. Lighting in the home can negatively affect health but the current evidence base is limited to a small number of studies in different domains of light and health. Further research surrounding specific health outcomes is required to better inform housing quality assessments and lighting practises in the home