Fatty Acids in Fish

The human body cannot synthesize certain fatty acids: these essential fatty acids must be consumed in the diet. Fish and other aquatic foods are known to be the main sources of polyunsaturated fatty acids (PUFA); therefore, humans obtain most of their eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) by consuming fish, aquatic invertebrates, and algae. The increasing demand for fish and the stabilization of marine fish and freshwater landings have contributed to a widening gap between demand and supply for fish and fish products. This leads to a necessity to improve aquaculture production. Fish are the main contributors of n‐3 PUFA in the human diet, although there are some interspecific and intraspecific differences in fatty acid profiles. The fatty acid composition of fish differs depending on a variety of factors, including species, diet, as well as environmental factors such as salinity, temperature, season, geographical location, and whether the fish are farmed or wild. In this chapter, information will be provided on fish fatty acids based on their ecology, feeding habits, lipid contents, and environmental conditions where they are harvested

The use of sesame oil in sea bream feeds and its effects on growth and body chemical composition

As fish oil availability declines worldwide and its price rises, there is a growing need to engage in scientific investigations into alternative oil sources for incorporation into fish feeds. This study aimed to determine the effects of dietary sesame oil on the growth performance, feed utilization, and nutritional composition of sea bream (*Sparus aurata*). Twenty-five individual fish (initial mean weight: 32.38±0.27 g) were placed in each tank in triplicate. Four experimental fish meal-based (iso-proteic 49% and iso-lipidic 20%) diets were formulated; the control (C) group contains 100% of fish oil (FO) and varying amounts (20, 40, 60%) of sesame oil (SO). During the 75-day experiment, the fish were fed 3 times a day, and the mean ambient temperature and dissolved oxygen values were measured as 22.5±0.5°C and 6.8±0.3 mg/L, respectively. At the beginning of the experiment, 20 fish were sampled to determine their nutrient composition and somatic indexes. In the end, 4 fish were collected for the same procedures and 4 for each tank's muscle and liver fatty acid compositions. At the end of the study, the S60 group exhibited the lowest final weight (FW) and feed utilization parameters. On the other hand, there were no statistical differences between FO, SO20, and SO40 in terms of FW. In addition, the SO40 group had the best feed conversion ratio (FCR) among the groups (P\<0.05). The whole-body lipid compositions of the groups were different. The highest lipid level was found in SO40 with 15.83±0.36%. Muscle and liver fatty acid composition was significantly affected by the fatty acid profile of experimental feeds. While total ω-6 fatty acids were higher in the SO groups than in group C, total ω-3 fatty acids were higher in the C group compared to the SO groups (P\<0.05). The ω-3/ω-6 ratios in the SO20 and SO40 groups showed similarity, while the highest ratio was observed in the control group (P\<0.05). As a result, according to data obtained from our study, it is predicted that 40% SO could be added to sea bream feed instead of FO in terms of growth performance, feed utilization, and nutritional composition

Potential of cottonseed oil as fish oil replacer in European Sea Bass feed formulation

Triplicate groups of 20 European sea bass (35 g) were fed five diets in which the added lipid was 100% fish oil (FO), 40% (CSO40), 60% (CSO60), 80% (CSO80) and 100% (CSO100) refined cottonseed oil (CSO), for a period of 120 days. Overall fish growth, feed conversion ratio and protein utilization were unaffected by dietary treatment, but hepatosomatic and visceral fat indexes increased with increasing dietary CSO. Fillet fatty acid composition of total lipids reflected the fatty acids in the test diets. The monounsaturated fatty acids were significantly higher in fillet of fish fed diet FO, CSO40 and CSO60 compared to other treatments while saturated and polyunsaturated fatty acids (PUFA) were not affected by the dietary treatment. Some fatty acids (18:0, 18:1n-9, 20:5n-3 and 22:6n-3) were present in higher concentration in fillet lipid than in the CSO100 dietary lipid indicating accumulation in fillet relative to test diets. Retention of n-3 LC-PUFA within the fillet was increasingly inefficient among fish fed increasing levels of FO. Thus, this study suggests that CSO can be considered as a relatively effective substitute for fish oil in European sea bass (35 g) in terms of growth performances and feed efficiency as far as fish meal is present in the diet

Farklı stoklama yoğunluklarının levrek (Dicentrarchus labrax, L.) fingerliklerinin gelişme performansları üzerine etkisi

TEZ3068Tez (Yüksek Lisans) -- Çukurova Üniversitesi, Adana, 1999.Kaynakça (s. 24-26) var.vi, 26 s. ; rnk. res. ; 30 cm.

An investigation on determination of different levels of dietary supplemental L-carnitine and lipid on growth performance and body chemical composition of gilthead sea bream (Sparus aurata).

TEZ5541Tez (Doktora) -- Çukurova Üniversitesi, Adana, 2005.Kaynakça (s. 94-104) var.ix, 105 s. ; 29 cm.Two different experiments were carried out in this study. 1st experiment dealt with the effect of different L-carnitine levels (0, 1, 2, 3 ve 4g/kg diet; G0, G1, G2, G3 ve G4 respectively) on growth performance and proximate composition of sea bream. The fish (5.29+/-0.97 g) were grown on experimental diets for 45 days in three replicates. The results showed that higher growth, weigth gain and feed efficiency were displayed by G3 and G4 than the other groups (P0.05). On the other hand, whole body composition results showed slight differencies between the initial and final protein composition of the fish. There was no clear effects of lipid or L-carnitine on fatty acid composition of the fish. In contrast, TAG and free fatty acids (FFA) results indicated that L-carnitine and lipid levels were affected in the fish liver and muscles. These neutral lipid classes were used more effectively when the lipid levels of the diets was increased.Bu çalışmada, iki farklı deneme kurgulanmıştır. I. denemede yemlere eklenen Lkarnitinin (0, 1, 2, 3 ve 4 g/kg yem; sırasıyla G0, G1, G2, G3 ve G4) çipura balıklarının büyüme performansları ve vücut kimyasal kompozisyonları üzerindeki etkileri araştırılmıştır. İlk denemede, 5,29+/-0,97 g ağırlığındaki balıklar, her grup için 3 tekerrür olacak şekilde stoklanarak 45 gün boyunca yemlenmişlerdir. Deneme sonucu verilerine göre, G3 ve G4'teki Son Ağırlık (SA), Canlı Ağırlık Kazancı (CAK) ve Yem Etkinlik Oranı (YEO)'nın diğer gruplara oranla daha iyi olduğu belirlenmiştir (P0,05). Tüm vücut kompozisyonları analizleri ise, balıkların kaslarındaki protein oranının deneme başındaki orana göre az da olsa arttığını göstermiştir. Yağ asitleri sonuçlarında yine L-karnitin ve yağ faktörlerinin belirgin etkileri gözlenmezken, sadece birkaç yağ asidi üzerine etkisi olmuş ve daha detaylı sonuçların alındığı nötral yağ asitleri verilerine göre, hem yağ hem de L-karnitin ilavesinin, balık kas ve karaciğerlerinde TAG ve Serbest Yağ Asitleri (SYA) değerlerini önemli derecede değiştirdiği, yemdeki yağ seviyesinin artmasıyla bu nötral yağ sınıflarının daha etkin bir şekilde kullanıldığı belirlenmiştir.Bu çalışma Ç.Ü. Bilimsel Araştırma Projeleri Birimi tarafından desteklenmiştir. Proje No: FBE2002D143

Farklı Açlık ve Yeniden Besleme Döngülerinin Avrupa Deniz Levreği (Dicentrarchus labrax) Vücut Kompozisyonu ve Büyümesi Üzerine Etkileri

Bu çalışma farklı açlık ve yeniden besleme döngülerinin, Avrupa deniz levreği jüvenilleri büyüme performansı ve vücut kimyasal kompozisyonları üzerine etkilerini araştırmak amacıyla tasarlanmıştır. Bu amaçla, başlangıç ortalama ağırlığı (BOA) 5,85±0,54 g olan toplam 720 adet jüvenil birey üç tekerrürlü gruplarda 12 adet tanka (400 L) ayrılmıştır. Deneme süresince, kontrol grubu (K) günde üç kez doyana kadar beslenmiştir. Diğer üç grubun besleme rejimi şu şekilde dizayn edilmiştir: 2 gün aç/8 gün tok (G1) (5 döngü), 5 gün aç/20 gün tok (G2) (2 döngü) ve 10 gün aç/40 gün tok (G3) (1 döngü). Elli gün sonrasında, sadece G1 grubu kısmi telafi büyümesi göstermiştir. Grupların son ağırlıkları (SA) arasındaki farklılık istatistiksel olarak önemli bulunmuştur (P0,05). Toplam yağ (TY) en düşük G3 grubunda bulunmuştur (P0.05). Total fat (TF) was lowest in G3 (<0.05). The partial compensation by group G1 presents possibilities for economic optimizatio

The effects of rate-restricted feeding regimes in cycles on digestive enzymes of gilthead sea-bream, Sparus aurata

In order to understand enzymatic alteration during the restricted-to-fed feeding schedules in cycles, the modulation of key enzyme activities in digestion was studied in different part of gastrointestinal track of juvenile gilthead sea bream (Sparus aurata). Juveniles (6.4 g) were stocked into 12 tanks at a density of 16 fish per tank. Four different feeding schedules were tested on triplicate groups of juvenile fish: (1) fish were fed to apparent satiation twice a day throughout 48 days, (2) starvation for 1 day and then re-fed for 2 days (S1), (3) 50% satiation for 2 days and then re-fed to apparent satiation for 2 days (R2), (4) 50% satiation for 6 days and then re-fed to apparent satiation for another 6 days (R6). The activity of total protease, amylase and lipase in the control group was higher than those S1 and R6 in whole gastrointestinal track. The restricted feeding in R2 enhanced the activities of lipase, amylase, and, to some extent, total protease in fish, with the mostly pronounced effect exhibited in the pyloric caeca. Generally, total protease and lipase activity of fish in R2 exhibited no significant difference compared to the control, except amylase activity in mid-intestine. Thus, because of preserved digestive enzyme activities, some food restriction (R2) cycles may be recommended as a routine procedure in commercial production of juvenile gilthead sea bream.In order to understand enzymatic alteration during the restricted-to-fed feeding schedules in cycles, the modulation of key enzyme activities in digestion was studied in different part of gastrointestinal track of juvenile gilthead sea bream (Sparus aurata). Juveniles (6.4 g) were stocked into 12 tanks at a density of 16 fish per tank. Four different feeding schedules were tested on triplicate groups of juvenile fish: (1) fish were fed to apparent satiation twice a day throughout 48 days, (2) starvation for 1 day and then re-fed for 2 days (S1), (3) 50% satiation for 2 days and then re-fed to apparent satiation for 2 days (R2), (4) 50% satiation for 6 days and then re-fed to apparent satiation for another 6 days (R6). The activity of total protease, amylase and lipase in the control group was higher than those S1 and R6 in whole gastrointestinal track. The restricted feeding in R2 enhanced the activities of lipase, amylase, and, to some extent, total protease in fish, with the mostly pronounced effect exhibited in the pyloric caeca. Generally, total protease and lipase activity of fish in R2 exhibited no significant difference compared to the control, except amylase activity in mid-intestine. Thus, because of preserved digestive enzyme activities, some food restriction (R2) cycles may be recommended as a routine procedure in commercial production of juvenile gilthead sea bream

Feed Additive Used in Fish Cultivation

With the increase of the world population, the need for food resources has increased. Fishing has also been associated with a rapid increase in fish consumption, as well as the presence of omega-3 and omega-6 fatty acids, which are essential for humans other than high-quality and high-vitamin, mineral and protein structure. It is observed that the quantities obtained from hunting decreased in the researches carried out and the increase in the amount of products grown against this occurred. One of the most important factors in the aquaculture breeding is the feed given to the cultivated species and the content of this feed. Fish meal and fish meal and fish meal are used in a significant amount. The inclusion of these feedstocks in fish feeds increases prices and, as a result, increases the cost of operating costs. Feed additives are added to the rations in order to better utilize the feed and reduce the feed costs in the feeding of the fish beside the feed raw materials. Restricting the use of antibiotics in animal nutrition has led to the preference of organic products for consumers. Probiotics, prebiotics, enzymes, antioxidants, preservatives, emulsifiers, stabilizers and organic acids are some of the alternative feed additives

Investigation of body compositions of three Tilapia species [(Tilapia rendalli (Boulenger,1896), Tilapia zilli (Gervais,1848), Oreochromis aureus (Steindacher,1864)] rared in cage condition in the Seyhan Dam Lake (Adana)

Bu çalışmada, Seyhan baraj gölüne yerleştirilmiş olan kafeslerde yetiştiriciliğe tabi tutulan ve ticari pelet yemlerle beslenmiş olan üç Tilapia türü (Tilapia rendalli, Tilapia zilli, Oreochromis aureus)'nün besinsel kompozisyonları incelenmiştir. Araştırma sonunda tüm türlerin kuru madde, ham protein, lipit ve ham kül düzeyleri belirlenmiş ve besinsel değerler arasında istatistiksel fark bulunmamıştır. Belirlenmiş olan besinsel değerler T. rendalli için, kuru madde; 26.056±0.215, ham protein; 20.523±0.465, lipid; 3.523±0.215 ve ham kül; 1.236±0.009, T. zilli için, kuru madde; 26.032±0.612, ham protein; 19.759±0.125, lipid; 3.339±0.403 ve ham kül; 1.214±0.070, O. aureus için, kuru madde; 24.498±0.643, ham protein; 20.202±0.051, lipid; 3.007±0.101 ve ham kül; 1.221±0.052.Investigation of body compositions of three Tilapia species (Tilapia rendalli (Boulenger, 1896), Tilapia zilli (Gervais, 1848), Oreochromis aureus (Steindachner, 1864)) rared in cage condition in the Seyhan Dam Lake (Adana). Body composition of three Tilapia species (Tilapia rendalli, Tilapia zilli, Oreochromis aureus) rared in cage condition in Seyhan dam lake were investigated in this study. At the and of the experiment, dry matter, crude protein, lipid and crude ash values were determined and the results indicated that there was no any significant differences between body composition values of the species. Body composition values were; dry matter; 26.056±0.215, crude protein; 20.523±0.465, lipid; 3.523±0.215 and crude ash; 1.236±0.009 for T. rendalli, dry matter; 26.032±0.612, crude protein; 19.759±0.125, lipid; 3.339±0.403 and crude ash; 1.214±0.070 for T. zilli, dry matter; 24.498±0.643, crude protein; 20.202±0.051, lipid; 3.007±0.101 and crude ash; 1.221±0.052) for O. aureus