Dietary Lipid Sources Research Articles

Effects of different lipid sources on growth performance, body composition and lipid metabolism of bullfrog Lithobates catesbeiana

Fish oil is the most important lipid source, but its limited supply and high cost has forced the feed industry to investigate alternative lipid sources. The goal of this study was therefore to investigate effects of different lipid sources on growth performance, feed digestibility, body composition and lipid metabolism of bullfrog Lithobates catesbeiana. Bullfrogs were fed five diets containing 5.2% of either fish oil (FO), poultry fat (PF), pork lard (PL), soybean oil (SO) or palm oil (PO) for 8weeks. Growth and feed utilization were significantly (P<0.05) affected by different lipid sources. Weight gain and feed intake of bullfrogs fed diets with FO, SO and PO showed no significant difference. Body composition, feed conversion ratio and protein efficiency ratio of bullfrog were not affected by lipid sources. Apparent digestibility coefficients (ADC) of diets and test lipid ingredients were significantly (P<0.05) different among all treatments; the highest ADC for lipid was observed in FO and SO, and the lowest value was found in PF. Fatty acid profiles of muscle reflected the fatty acid composition of dietary lipid source. The activities of hepatic enzymes related to lipid metabolism were significantly affected (P<0.05) by lipid sources; the PF and PL groups had lower activities, compared to other groups. In conclusion, this study shows that fish oil can be totally replaced by SO or PO in bullfrog diets for a period of 8weeks without negatively affecting growth performance. These alternative lipid sources have no effect on the body composition of bullfrog, while the fatty acid composition of muscle could be modified by lipid sources. Moreover, lipid sources could affect hepatic lipid metabolism of bullfrog.

Effect of diets containing laurel seed oil on growth and fatty acid composition of rainbow trout,Oncorhynchus mykiss

The aim of this study was to determine the effects of replacing fish oil (FO) with laurel seed oil (LSO), as an alternative plant lipid source in diets on the growth and fatty acid composition of rainbow trout (Oncorhynchus mykiss; 111.47 ± 0.2 g mean individual weight). At the end of the feeding trial, survival was 100% in all treatments. No significant differences were seen in growth between the dietary groups (P > 0.05). The protein, lipid and ash contents were not significantly different among the groups (P > 0.05); however, there was a significant difference in protein and ash content between the treatment groups and the initial, and between the 50LSO group and the initial group, respectively (P 0.05). Based on the results of growth performance and fatty acid composition of the experimental fish in this study, it can be concluded that the 75% concentration of laurel seed oil performed best among the diets tested in the experiment.

Blood Lipid Components and SREBP-1 Gene Expression in Broiler Chickens Fed Different Dietary Lipid Sources

Background: Liver plays an important role in energy homeostasis. Intense liver diseases are accompanied with lower concentrations of n-3 and n-6 poly unsaturated fatty acids (PUFA). It has been found that n-3 PUFA play importantly protective roles in the liver. There was limited information about the effects of lipid sources on serum lipid components and liver sterol regulatory element binding-1 (SREBP-1) gene expression. Therefore, the aim of this study was to evaluate and compare the effects of fish oil, corn oil, olive oil and tallow, respectively, as dietary sources of n-3, n-6, n-9 and saturated fatty acid on serum lipid compound and liver SREBP-1 gene expression in broiler chicks.Materials, Methods &amp; Results: In a completely randomized design, 240 one-day-old broiler chicks were allocated to five dietary treatments, four replicates and 12 chicks per each. Dietary treatments included of: control (diet without lipid supplementation) and diet supplemented with fish oil as a n-3 fatty acid source, corn oil as a n-6 fatty acid source, olive oil as a n-9 fatty acid source and tallow as a saturated fatty acid which were added to diets at 1.5, 3 and 4% in the starter, grower and finisher, respectively. At days 28 and 42 of age, liver tissue was dissected out and samples were placed in liquid nitrogen, also blood samples were collected. The SREBP-1 mRNA expression in liver tissue was quantitated using RT-PCR. Broilers fed diets containing fish oil, corn oil and olive oil as unsaturated fatty acid sources had lower concentrations of triacylglycerol than those fed other diets. Also, diets containing fish oil and tallow showed the lowest low density lipoprotein (LDL) levels at day 28 of age. Diets containing corn oil and olive oil showed higher levels of cholesterol and high density lipoprotein (HDL) than other diets but, these differences were not significant at days 28 and 42 of age (P ≥ 0.05). In both sampling periods, the chickens fed diets containing tallow expressed higher (P &lt; 0.05) SREBP-1 gene as compared to those fed other dietary lipids. Broilers fed diet containing corn oil had higher (P &lt; 0.05) SREBP-1 gene expression than those fed diet containing fish oil and olive oil.Discussion: Serum lipids were affected by dietary fat source. Lower concentration of serum triacylglycerols was found in broilers fed fish oil and corn oil diets as dietary n-3 and n-6 fatty acid sources. It was shown that dietary PUFA, especially n-6 and n-3 fatty acids could reduce hepatic fatty acid and triacylglycerol synthesis. Broilers fed corn oil diet showed elevated LDL levels respect with those fed fish oil or tallow at day 28 of age. The results showed that dietary polyunsaturated fatty acids and saturated fatty acids substantially affected on SREBP-1 gene expression at days 28 and 42 of age. The birds fed fish oil as n-3 PUFA source expressed lower SREBP-1 gene compared with other groups at day 28 of age. Longer chain length, high number of double bonds, and the presence of the first double bond gives these fatty acids distinct and unique properties that separate them and their metabolic products from the more common n-6 and n-9 fatty acids. The finding of this study indicated lipogenic effects of tallow and then corn oil. The results confirmed that each of dietary lipid sources had different effect on serum lipid components. It was also found that SREBP-1 gene expression is age-dependent and it increased as age of broilers increased.

Scavenger Receptor Class B, Type I, a CD36 Related Protein in Macrobrachium nipponense: Characterization, RNA Interference, and Expression Analysis with Different Dietary Lipid Sources.

The scavenger receptor class B, type I (SR-BI), is a member of the CD36 superfamily comprising transmembrane proteins involved in mammalian and fish lipid homeostasis regulation. We hypothesize that this receptor plays an important role in Macrobrachium nipponense lipid metabolism. However, little attention has been paid to SR-BI in commercial crustaceans. In the present study, we report a cDNA encoding M. nipponense scavenger receptor class B, type I (designated as MnSR-BI), obtained from a hepatopancreas cDNA library. The complete MnSR-BI coding sequence was 1545 bp, encoding 514 amino acid peptides. The MnSR-BI primary structure consisted of a CD36 domain that contained two transmembrane regions at the N- and C-terminals of the protein. SR-BI mRNA expression was specifically detected in muscle, gill, ovum, intestine, hepatopancreas, stomach, and ovary tissues. Furthermore, its expression in the hepatopancreas was regulated by dietary lipid sources, with prawns fed soybean and linseed oils exhibiting higher expression levels. RNAi-based SR-BI silencing resulted in the suppression of its expression in the hepatopancreas and variation in the expression of lipid metabolism-related genes. This is the first report of SR-BI in freshwater prawns and provides the basis for further studies on SR-BI in crustaceans.

Quantitative analysis of ruminal bacterial populations involved in lipid metabolism in dairy cows fed different vegetable oils

Vegetable oils are used to increase energy density of dairy cow diets, although they can provoke changes in rumen bacteria populations and have repercussions on the biohydrogenation process. The aim of this study was to evaluate the effect of two sources of dietary lipids: soybean oil (SO, an unsaturated source) and hydrogenated palm oil (HPO, a saturated source) on bacterial populations and the fatty acid profile of ruminal digesta. Three non-lactating Holstein cows fitted with ruminal cannulae were used in a 3×3 Latin square design with three periods consisting of 21 days. Dietary treatments consisted of a basal diet (Control, no fat supplement) and the basal diet supplemented with SO (2.7% of dry matter (DM)) or HPO (2.7% of DM). Ruminal digesta pH, NH3–N and volatile fatty acids were not affected by dietary treatments. Compared with control and HPO, total bacteria measured as copies of 16S ribosomal DNA/ml by quantitative PCR was decreased (P<0.05) by SO. Fibrobacter succinogenes, Butyrivibrio proteoclasticus and Anaerovibrio lipolytica loads were not affected by dietary treatments. In contrast, compared with control, load of Prevotella bryantii was increased (P<0.05) with HPO diet. Compared with control and SO, HPO decreased (P<0.05) C18:2 cis n-6 in ruminal digesta. Contents of C15:0 iso, C18:11 trans-11 and C18:2 cis-9, trans-11 were increased (P<0.05) in ruminal digesta by SO compared with control and HPO. In conclusion, supplementation of SO or HPO do not affect ruminal fermentation parameters, whereas HPO can increase load of ruminal P. bryantii. Also, results observed in our targeted bacteria may have depended on the saturation degree of dietary oils.

Effect of Dietary Lipid Sources on Body Fatty Acid Composition of Chinese Longsnout Catfish Leiocassis longirostris

Abstract We investigated the effects of dietary lipid sources on growth and fatty acid composition of juvenile Chinese longsnout catfish. Triplicate groups of fish (initial average weight, 3.8 g) were fed four diets containing either fish oil (FO), soybean oil (SO), linseed oil (LO) and lauric acid (LA) for 10 weeks. There were no differences among the groups in body weight, feed intake, feed effi-ciency, protein efficiency ratio, and body proximate composition of fish fed the diets containing different lipid sources ( P > 0.05) during the study. However, fatty acids compositions of the whole body were influenced by dietary lipid source. Fish fed the SO diet had high concentration of linoleic acid, whereas those of fish fed the LO diet were rich in linolenic acid and arachidonic acid. Fish fed the FO diet had significantly ( P < 0.05) higher levels of monounsaturated fatty acids such as 18:1n-9 and 20:1n-9 than those of fish fed the SO and LO diets. Eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) composition of body were not influenced by dietary lipid source. The results suggest that each of FO, SO, LO or LA can be used as a lipid source in the diets of Chinese longsnout catfish without any negative effects on growth and feed utilization and these data demonstrate the potential impact which dietary fat composition can change the body fatty acid profile.

Unrefined Peanut Oil as a Lipid Source in Diets for Juveniles of Two‐banded Seabream Diplodus vulgaris

AbstractA feeding study with Two‐banded Seabream Diplodus vulgaris was conducted to determine the effects of replacement of fish oil (FO) by unrefined peanut oil (PO) on growth performance, feed utilization, body composition, fatty acid composition, and serum biochemical and hematological variables. Three isonitrogenous (35.8%) and isoenergetic (21.15 kJ/g) diets were formulated by replacing dietary FO with PO at levels of level 0% (PO0), 50% (PO50), or 100% (PO100). Fish were fed twice a day until satiation for an experimental period of 8 weeks. The best growth performance was observed in fish fed with the PO0 and PO50 diets. A significant increase was observed in hematocrit and mean corpuscular volume levels of fish fed with PO50 diet compared with the other groups. Hemoglobin, mean corpuscular hemoglobin, total protein, albumin, and globulin were not affected by dietary PO treatment and did not differ among experimental groups. The glucose level was highest in the PO100 group. Triglyceride and cholesterol levels were lower in fish fed diets with PO inclusions than in those fed the control diet. The fatty acid composition of fish was significantly affected by the experimental diets. Glutamic oxaloacetic transaminase, glutamic pyruvictransaminase, lactate dehydrogenase, and alkaline phosphatase were not affected by dietary PO treatment. The n‐3:n‐6 ratio in fish fed the PO0 diet was also higher than in fish fed the PO‐supplemented diets. The results of the present study showed that FO could be substituted by PO up to 50% in Two‐banded Seabream diets without any negative effect on growth performance or serum biochemical and hematological features.

Dietary Fatty Acid Metabolism is Affected More by Lipid Level than Source in Senegalese Sole Juveniles: Interactions for Optimal Dietary Formulation.

This study analyses the effects of dietary lipid level and source on lipid absorption and metabolism in Senegalese sole (Solea senegalensis). Juvenile fish were fed 4 experimental diets containing either 100 % fish oil (FO) or 25 % FO and 75 % vegetable oil (VO; rapeseed, linseed and soybean oils) at two lipid levels (~8 or ~18 %). Effects were assessed on fish performance, body proximate composition and lipid accumulation, activity of hepatic lipogenic and fatty acid oxidative enzymes and, finally, on the expression of genes related to lipid metabolism in liver and intestine, and to intestinal absorption, both pre- and postprandially. Increased dietary lipid level had no major effects on growth and feeding performance (FCR), although fish fed FO had marginally better growth. Nevertheless, diets induced significant changes in lipid accumulation and metabolism. Hepatic lipid deposits were higher in fish fed VO, associated to increased hepatic ATP citrate lyase activity and up-regulated carnitine palmitoyltransferase 1 (cpt1) mRNA levels post-prandially. However, lipid level had a larger effect on gene expression of metabolic (lipogenesis and β-oxidation) genes than lipid source, mostly at fasting. High dietary lipid level down-regulated fatty acid synthase expression in liver and intestine, and increased cpt1 mRNA in liver. Large lipid accumulations were observed in the enterocytes of fish fed high lipid diets. This was possibly a result of a poor capacity to adapt to high dietary lipid level, as most genes involved in intestinal absorption were not regulated in response to the diet.

Dietary Olive and Perilla Oils Affect Liver Mitochondrial DNA Methylation in Large Yellow Croakers1–3

Background: Substantial progress has been made in nutritional epigenetics, but little is known regarding whether mitochondrial DNA (mtDNA) methylation is involved in this process.Objective: The objective of this study was to determine whether dietary lipid sources [various fatty acids (FAs)] modify mtDNA methylation.Methods: A total of 600 large yellow croakers (Larimichthys crocea) with an average initial weight of 151 ± 4 g were fed 1 of 5 diets (3 replicate cages/treatment) containing either fish oil (FO) (control), palmitic acid, olive oil (OO), sunflower oil, or perilla oil (PO) as the dietary lipid source (12% dry weight of the diet) for 70 d. Pyrosequencing was used to determine the effects of dietary lipid sources (FAs) on mtDNA methylation.Results: Mitochondrial arginine transfer RNA and NAD(H) dehydrogenase 4L encoding region methylation in the liver was higher in the OO (9.5% ± 0.52%; P < 0.05) and PO (7.3% ± 0.33%; P < 0.05) groups than in the FO (5.9% ± 0.42%) group, whereas 12S ribosomal RNA (rRNA) methylation in the liver was lower in the OO group (2.7% ± 0.22%) than in the FO group (4.2% ± 0.73%) (P < 0.05). Additionally, fish fed the OO diet had lower liver mRNA levels of ND3 (P < 0.05), ND4L (P < 0.05), ND6 (P < 0.05), 12S rRNA (P < 0.05), and 16S rRNA (P < 0.05) than those fed the FO diet, whereas fish fed the PO diet had lower liver mRNA levels of 16S rRNA than those fed the FO diet (P < 0.05). Moreover, fish fed the OO (P < 0.05) or PO (P < 0.05) diet had lower liver mitochondrial complex I activity than did those fed the FO diet.Conclusions: These findings provide the first evidence, to our knowledge, that dietary lipid sources influence mitochondrial function through mtDNA methylation in large yellow croakers.

Evaluation of different lipid sources in diet of pacific white shrimp Litopenaeus vannamei at low salinity

Litopenaeus vannamei (1.98±0.28g) were fed diets containing soybean oil (SBO), beef tallow (BFT), fish oil (FIO), linseed oil (LNO), and an equal combination of SBO+BFT+FIO (SBF) or SBO+BFT+LNO (SBL) as dietary lipid source respectively for 8 weeks at low salinity of 3‰. The shrimp fed the SBL diet had the highest weight gain and survival rate. The whole body fatty acid composition including the EPA and DHA of L. vannamei generally reflected the composition of dietary fatty acids with the highest DHA and EPA found in L. vannamei fed FIO. The activities of fatty acid synthetase, acyl-CoA, diacylgycerol acyltransferase 2, elongase of long-chain fatty acids family member 6, Δ5 and Δ6 fatty acid desaturases of shrimp fed SBL were significantly lower than those fed BFT. The results indicated that fish oil could not be the only lipid source for L. vannamei cultured at low salinity, and the shrimp fed non-fish oil diet with a suitable proportion of PUFAs could obtain the same growth and survival rate as those fed diets with fish oil.

In vivo regulation of colonic cell proliferation, differentiation, apoptosis, and P27Kip1 by dietary fish oil and butyrate in rats.

We have shown that dietary fish oil is protective against experimentally induced colon cancer, and the protective effect is enhanced by coadministration of pectin. However, the underlying mechanisms have not been fully elucidated. We hypothesized that fish oil with butyrate, a pectin fermentation product, protects against colon cancer initiation by decreasing cell proliferation and increasing differentiation and apoptosis through a p27(Kip1)-mediated mechanism. Rats were provided diets of corn or fish oil, with/without butyrate, and terminated 12, 24, or 48 hours after azoxymethane (AOM) injection. Proliferation (Ki-67), differentiation (Dolichos Biflorus Agglutinin), apoptosis (TUNEL), and p27(Kip1) (cell-cycle mediator) were measured in the same cell within crypts in order to examine the coordination of cell cycle as a function of diet. DNA damage (N(7)-methylguanine) was determined by quantitative IHC analysis. Dietary fish oil decreased DNA damage by 19% (P = 0.001) and proliferation by 50% (P = 0.003) and increased differentiation by 56% (P = 0.039) compared with corn oil. When combined with butyrate, fish oil enhanced apoptosis 24 hours after AOM injection compared with a corn oil/butyrate diet (P = 0.039). There was an inverse relationship between crypt height and apoptosis in the fish oil/butyrate group (r = -0.53, P = 0.040). The corn oil/butyrate group showed a positive correlation between p27(Kip1) expression and proliferation (r = 0.61, P = 0.035). These results indicate the in vivo effect of butyrate on apoptosis and proliferation is dependent on dietary lipid source. These results demonstrate the presence of an early coordinated colonocyte response by which fish oil and butyrate protects against colon tumorigenesis.

Evaluation of fish meal and fish oil replacement by soybean protein and algal meal from Schizochytrium limacinum in diets for giant grouper Epinephelus lanceolatus

Sparing marine-origin protein and lipid was investigated in diets for giant grouper (Epinephelus lanceolatus), using various combinations of soybean meal (SBM), soy protein concentrate (SPC), and an algal meal derived from Schizochytrium limacinum (ALG) to replace fish meal (FM), squid meal (SQM) and fish oil (FO). Diets were formulated to contain 45% protein (dry weight) and 10% lipid. Three diets were derived from this formulation, using combinations of SBM, SPC, and ALG to replace 20% (FM80), 40% (FM60), or 80% (FM20) of the marine-origin protein sources; additionally, incorporation of the lipid-dense ALG resulted in complete FO replacement in the FM60 and FM20 diets. A feeding experiment was carried out in a seawater recirculating system with 12, 90-L tanks initially stocked with 6 fish each (individual weight=45.9±7.1g) and maintained at 25°C. Diets were assigned to tanks in triplicate, fish were fed to apparent satiation twice daily for 12weeks, and growth rate, body composition, nutrient retention, survival, hepatosomatic index and intestinal integrity were subsequently evaluated. With the exception of retained lipid, the FM100, FM80, and FM60 diets all yielded equivalent (P>0.05) growth and feed utilization. In comparison, weight gain, specific growth rate, feed intake, retained nitrogen and retained lipid were significantly reduced in fish fed the FM20 feed, whereas FCR was significantly elevated. Amino acid analysis of the diets indicated that methionine was limiting in the FM20 feed. Hepatosomatic index did not vary among treatments, but other aspects of body composition were affected. Carcass lipid and ash significantly decreased with marine ingredient inclusion; carcass protein also varied, though less appreciably and without a clear pattern. Fillet fatty acid profile reflected dietary composition. The FM100 diet yielded the highest fillet EPA content, whereas DHA content, DHA:EPA and n−3:n−6 ratios, and total long-chain polyunsaturated fatty acids increased with dietary inclusion of ALG. Histological analysis revealed progressive morphological changes to the distal intestine with higher levels of FM replacement, suggesting enteritis among fish fed the FM20 feed. It is concluded that a blend of SBM, SPC, and ALG can replace at least 40% of marine protein sources, and ALG can be used as the main lipid source in diets for E. lanceolatus without significantly affecting fish performance or condition. Statement of relevanceThe results of this work contribute to decrease the dependence on protein and lipids from reduction fisheries traditionally used in commercial feeds for carnivorous fish, potentially improving the sustainability of aquaculture production of marine fish.

Partial or total replacement of dietary fish oil with alternative lipid sources in silvery-black porgy (Sparidentex hasta)

An eight-week feeding trial was conducted to evaluate the effects of partial (50%) or total (100%) replacement of dietary fish oil with alternative lipid sources in silvery-black porgy. Seven isonitrogenous (50%) and isolipidic (20%) experimental diets were formulated namely: FO (fish oil), CO (canola oil), SO (sunflower oil), T (tallow), FC (fish oil+canola oil, 50:50), FS (fish oil+sunflower oil, 50:50) and FT (fish oil+tallow, 50:50). Fish fed the T and FT diets statically had lower final weight, weight gain and specific growth rate than other groups (P<0.05); Fish fed FT diet had the highest feed conversion ratio (P<0.05). Fish fed the CO and SO diets had the highest and the lowest whole body and muscle protein content, respectively (P<0.05). Fillet and liver n−9 monounsaturated fatty acids, n−6 and n−3 poly unsaturated fatty acids were highest in fish fed the CO, SO and FO, respectively (P<0.05). Apparent digestibility coefficient of protein and lipid, hemolytic and bactericidal activities were lowest in fish fed the T diet (P<0.05). From the above results, it is suggested that the vegetal oil sources are recommended for total and partial replacement of FO in silvery-black porgy diets, whereas tallow is not advisable as an alternative lipid source in this species. Statements of relevanceIt is essential to introduce alternative lipid sources, to meet increasing global demands of aquafeeds for the sustainability of aquaculture industry. Thus, the aim of present study was to provide insight into the possibility of the use of alternative lipid sources in diet for silvery-black porgy juveniles by evaluating the growth performance, feed utilization, body composition and hemato-immunological parameters.

Dietary carbohydrate and lipid sources affect differently the oxidative status of European sea bass (Dicentrarchus labrax) juveniles.

This study aimed to evaluate the effects of dietary lipid source and carbohydrate content on the oxidative status of European sea bass (Dicentrarchus labrax) juveniles. For that purpose, four diets were formulated with fish oil (FO) and vegetable oils (VO) as the lipid source and with 20 or 0 % gelatinised starch as the carbohydrate source, in a 2×2 factorial design. Liver and intestine antioxidant enzyme activities (catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPX), glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD)), hepatic and intestinal lipid peroxidation (LPO), as well as hepatic oxidative stress index (OSI), were measured in fish fed the experimental diets for 73 d (n 9 fish/diet). Carbohydrate-rich diets promoted a decrease in hepatic LPO and OSI, whereas the lipid source induced no changes. Inversely, dietary lipid source, but not dietary carbohydrate concentration, affected LPO in the intestine. Lower intestinal LPO was observed in VO groups. Enzymes responsive to dietary treatments were GR, G6PD and CAT in the liver and GR and GPX in the intestine. Dietary carbohydrate induced GR and G6PD activities and depressed CAT activity in the liver. GPX and GR activities were increased in the intestine of fish fed VO diets. Overall, effects of diet composition on oxidative status were tissue-related: the liver and intestine were strongly responsive to dietary carbohydrates and lipid sources, respectively. Furthermore, different metabolic routes were more active to deal with the oxidative stress in the two organs studied.

Dietary carbohydrate and lipid source affect cholesterol metabolism of European sea bass (Dicentrarchus labrax) juveniles.

Plant feedstuffs (PF) are rich in carbohydrates, which may interact with lipid metabolism. Thus, when considering dietary replacement of fishery by-products with PF, knowledge is needed on how dietary lipid source (LS) and carbohydrates affect lipid metabolism and other metabolic pathways. For that purpose, a 73-d growth trial was performed with European sea bass juveniles (IBW 74 g) fed four diets differing in LS (fish oil (FO) or a blend of vegetable oils (VO)) and carbohydrate content (0 % (CH-) or 20 % (CH+) gelatinised starch). At the end of the trial no differences among diets were observed on growth and feed utilisation. Protein efficiency ratio was, however, higher in the CH+ groups. Muscle and liver fatty acid profiles reflected the dietary LS. Dietary carbohydrate promoted higher plasma cholesterol and phospholipids (PL), whole-body and hepatic (mainly 16 : 0) lipids and increased muscular and hepatic glycogen. Except for PL, which were higher in the FO groups, no major alterations between FO and VO groups were observed on plasma metabolites (glucose, TAG, cholesterol, PL), liver and muscle glycogen, and lipid and cholesterol contents. Activities of glucose-6-phosphate dehydrogenase and malic enzyme - lipogenesis-related enzymes - increased with carbohydrate intake. Hepatic expression of genes involved in cholesterol metabolism was up-regulated with carbohydrate (HMGCR and CYP3A27) and VO (HMGCR and CYP51A1) intake. No dietary regulation of long-chain PUFA biosynthesis at the transcriptional level was observed. Overall, very few interactions between dietary carbohydrates and LS were observed. However, important insights on the direct relation between dietary carbohydrate and the cholesterol biosynthetic pathway in European sea bass were demonstrated.

Effects of feeding different lipid sources on hepatic histopathology features and growth traits of broiler chickens

The effects of different dietary lipid sources on growth traits and hepatic histopathology of broiler chickens were investigated. Hubbard strain one-day old chickens (n=120) were kept in pens and were fed one of the three corn-soybean meal-based diets until 49 days of age. The dietary treatments consisted of 2.5% added oil or fat from three sources as follows: SFO diet containing sunflower oil; LRD diet containing lard, and EVOO diet containing extra-virgin olive oil. Dietary oil or fat type improved significantly body weight and gain as well as feed efficiency in birds fed EVOO compared to those fed the other treatments. Based on our findings, after the whole experimental feeding period it was possible to observe relevant injuries to the liver of the chicks fed with lard, whereas the hepatic histopathological changes appeared less marked or absent in the chicks fed vegetable oils from sunflower or olive. Thus, we can conclude that dietary lipid source affected chicks performance and hepatic histopathology especially when chicks fed diet containing animal fats; whereas feeding extra-virgin olive oil supported positively growth traits and did not result in hepatic histopathological effects.

Biofloc contribution to antioxidant defence status, lipid nutrition and reproductive performance of broodstock of the shrimp Litopenaeus stylirostris: Consequences for the quality of eggs and larvae

The aim of this study was to determine biofloc contributions to the antioxidant status and lipid nutrition of broodstock of Litopenaeus stylirostris in relationship with their reproductive performance and the health of larvae produced. Shrimp broodstock reared with BioFloc Technology (BFT) compared to Clear Water (CW) exhibited a higher health status with (i) a better final survival rate during the reproduction period (52.6% in CW against 79.8% in BFT); (ii) higher glutathione level (GSH) and total antioxidant status (TAS); (iii) reduced oxidized/reduced glutathione ratio; and (iv) a higher spawning rate and frequency as well as higher gonado-somatic index and number of spawned eggs. Finally, larvae from broodstock from BFT exhibited higher survival rates at the Zoe 2 (+37%) and Post Larvae 1 (+51%) stages when compared with those from females from CW treatment. The improved reproductive performance of the broodstock and higher larvae survival rate resulting from BFT treatment may be linked to the dietary supplement obtained by the shrimp from natural productivity during BFT rearing. Indeed, our study confirms that biofloc particulates represent a potential source of dietary glutathione and a significant source of lipids, particularly essential phospholipids and n−3 highly unsaturated fatty acids (HUFAs) for shrimps. Thus, broodstock from BFT treatment accumulated phospholipids, n−3 HUFA and arachidonic acid, which are necessary for vitellogenesis, embryogenesis and pre-feeding larval development. The predominant essential fatty acids, arachidonic acid (ARA), eicopentaenoic acid (EPA) and docosahexaenoic acid (DHA), had levels in the eggs that were, respectively, 2.5, 2.8 and 3 fold higher for BFT compared to the CW treatment. Statement of relevanceToday, the influence of biofloc technology on shrimp broodstock is not described enough and no information was available on the larvae quality.Moreover, two key pieces of new information emerge from the present study. Firstly, biofloc is a source of further dietary lipids that can act as energetic substrates, but also as a source of phospholipids and essential fatty acids necessary to sustain reproduction, embryonic and larval development. Second, improving the reproduction of the broodstock also leads to an improvement in the quality of the larvae.We think that our research is new and important to increase knowledge on biofloc topic. We believe that the paper will contribute to the development of more efficient and therefore more sustainable systems.

The orexinergic system in rainbow trout Oncorhynchus mykiss and its regulation by dietary lipids.

In this study, we report the distribution of orexin A (OXA), orexin B (OXB), and orexin receptor (OX2R) immunoreactive (ir) cells in the hypothalamus and gastrointestinal tract of Oncorhynchus mykiss fed diets with different dietary fatty acid compositions. Trout were fed five iso-energetic experimental diets containing fish oil, or one of four different vegetable oils (olive, sunflower, linseed, and palm oils) as the added dietary lipid source for 12 weeks. OXA, OXB, and OX2R immunoreactive neurons and nervous fibers were identified in the lateral and ventro-medial hypothalamus. OXA, OXB, and OX2R ir cells were found in the mucosa and glands of the stomach and in the mucosa of both the pyloric cecae and intestine. OX2R ir cells were localized in the mucosa layer of both the pyloric cecae and intestine. These immunohistochemical (IHC) results were confirmed via Western blotting. Antibodies against preproorexin (PPO) crossreacted with a band of ∼16 kDa in the hypothalamus, stomach, pyloric cecae, and intestine. Antibodies against OX2R crossreacted with a band of ∼38 kDa in the hypothalamus, pyloric cecae, and intestine. The presence and distribution of OXA, OXB, and OX2R ir cells in the hypothalamus and gastrointestinal tract did not appear to be affected by dietary oils. The presence of orexin system immunoreactive cells in the stomach, pyloric cecae, and intestine of rainbow trout, but not in the enteric nervous system, could suggest a possible role of these peptides as signaling of gastric emptying or endocrine modulation, implying a main local action played by orexins.

Evaluation of lipid sources in diets fed to bull trout,Salvelinus confluentus

To aid in development of nutritionally complete diets, a 12-week experiment was conducted to identify appropriate sources of dietary lipid for bull trout. The basal diet was top-coated with marine fish oil (MFO) (pollock liver oil), canola oil (CO), linseed oil (LO) or a mixture of canola and linseed oils (CLO) to produce four treatments. Each diet was fed to triplicate groups of fish initially averaging 1.6 g per fish. Weight gain, feed efficiency, survival and carcass proximate composition were not significantly different among fish fed the dietary treatments. However, whole-body fatty acid percentages varied significantly among fish fed the four diets. Whole bodies of fish fed diets with vegetable oil (VO) contained significantly higher 18:2n-6, 18:3n-3 and total n-6 polyunsaturated fatty acid percentages and significantly lower 20:5n-3, 22:6n-3 and total saturated fatty acid percentages compared with fish fed the MFO diet. Whole-body fatty acid percentages also varied among fish fed VO diets. Despite similar 18:2n-6 and 20:4n-6 percentages in the VO diets, fish fed diet CO contained significantly lower 18:2n-6 proportions and significantly higher 20:4n-6 proportions compared with fish fed other VO diets. Results of this study suggest dietary fish oil is not required for short-term rearing of bull trout.

Effect of Dietary Safflower and Canola Oil on Growth Performance, Body, and Fatty Acid Composition of Rainbow Trout (Oncorhynchus mykiss)

The objective of the present study was to evaluate the effects of the diets enriched with safflower and canola oil on growth, feed utilization, body composition, liver, and muscle fatty acid composition of rainbow trout (Oncorhynchus mykiss). Rainbow trout having approximate initial weight of 97.03 ± 0.10 g were fed the experimental diets containing only fish oil (Group 0SFO), safflower oil (50% safflower oil, Group 50SFO and 33% safflower oil, Group 33SFO), and vegetable oil blend (33% safflower and 33% canola oil, Group 66SFCO) for 45 days. Twenty-five fish were randomly assigned for triplicate treatments and offered the test diets two times daily to apparent satiation. At the end of the experiment, survival was 100% in all treatments. No significant differences in the weight gain, specific growth rate, feed conversion ratio, and protein efficiency ratio were found between fish fed with the different experimental diets. The highest hepatosomatic index (HIS) and viscerasomatic index (VSI) was obtained in 50SFO and 33SFO groups, respectively. The moisture, protein, lipid, and ash content in the body composition of the fish increased in all experimental groups. The lipid content was not significantly different among the groups (p > 0.05); however, there was a significant difference in ash content between the control and the other groups (p < 0.05). The experimental diets containing vegetable oil (50SFO and 33SFO groups) and vegetable oil blend (66SFCO group) had significantly higher concentrations of n-6 fatty acids, predominantly in the form of linoleic acid (LA). The n-3 fatty acids were present in significantly higher concentration in the control treatment (0SFO). The fatty acid composition of fish fillet and liver were reflective of the dietary lipid source. While the fillet and liver of fish fed the 50SFO diet was high in linoleic acid (18:2 n-6), fish fed the 66SFCO diet had high concentrations of oleic acid (OA; 18:1 n-9). The present study suggests that fish oil can be replaced by up to 50% with safflower oil and by up to 66% with safflower + canola oil blend in rainbow trout diets with no significant effect on growth.