Effects Of Dietary Lipid Sources Research Articles

Effects of Various Lipid Sources and L-Carnitine Supplementation on the Growth Performance, Body Composition, and Antioxidants Enzyme Ability of Dog Conch Larvae, Laevistrombus canarium

A feeding experiment was conducted to study the effects of dietary lipid sources and L-carnitine on the growth performance, body component, muscle fatty acid composition, and antioxidant enzyme ability of average weight of 0.28 g dog conch larvae, Laevistrombus canarium. Three sources of lipid: fish oil, soybean oil, and beef tallow were tested in combination with two levels (0 and 0.5%) of L-carnitine. The dog conch larvae fed diets containing fish oil with L-carnitine supplementation exhibited the highest weight gain. After air exposure challenge, the liver tissue of dog conch fed the diets containing soybean oil and beef tallow without supplemented L-carnitine had lower levels of superoxide dismutase (SOD, U min−1), phenoloxidase (PO, U min−1), and glutathione peroxidase (GPx, mU/mL) activity. The activity of SOD, PO, and GPx of dog conch larvae increased with increasing levels of dietary L-carnitine. In particular, dog conch larvae fed the diet containing fish oil supplemented with L-carnitine exhibited significantly ( P < 0.05 ) enhanced antioxidant responses. The thiobarbituric acid reactive substances (TBARS) in the muscle tissue of dog conch larvae fed the diet containing fish oil without L-carnitine supplementation showed significantly ( P < 0.05 ) higher activity. It was concluded that dietary administration of L-carnitine can enhance resistance against beta-oxidation, and the administration of fish oil in the diet was the best strategy to promote growth due to high nutritional availability.

Effect of Dietary Lipid Sources and Their Combinations on Growth and Fatty Acid Composition of Milkfish (Chanos chanos) Larvae

Background: The success of larval rearing is greatly influenced by first feeding regimes and the nutritional quality of weaning diets, with dietary lipids being recognized as one of the most important nutritional factors that affect larval growth and survival. Reports are scanty on milkfish larval nutrition and growth and survival unlike other marine species. Methods: In this investigation during 2020, five larval diets were prepared with 40 g kg-1 of entirely fish oil (F4), corn oil (C4) or fish oil and corn oil in 3:1 (F3C1), 2:2 (F2C2) and 1:3 (F1C3) ratios. Each diet was fed to triplicate groups of milkfish larvae (45 mg) in a flow-through rearing system for 42 days. Result: A growth indices were highest in the F3C1 group, followed by F2C2, F4 and other dietary treatments. The whole-body fatty acid profile was found to change significantly with increasing fish oil replacement with corn oil, i.e., the n-3 polyunsaturated and saturated fatty acid proportions decreased linearly, while the n-6 polyunsaturated fatty acids content increased. Overall, this study reveals that growth and survival of milkfish is dependent on dietary lipid source or combinations that meet the essential fatty acid requirements during the early life stages.

Effects of Dietary Lipid Sources on the Growth, Gonad Development, Fatty Acid Composition and Spawning Performance of Broodstock, and Early Larvae Quality of Sea Urchin (Strongylocentrotus intermedius)

This study was carried out to investigate the effects of five formulated feeds with different lipid sources (colza oil (CO), fish oil (FO), linseed oil (LO), soybean oil (SO), or palm oil (PO)) and kelp (Laminaria japonica) on the growth, reproductive performance of broodstock, and early larvae quality of sea urchin (Strongylocentrotus intermedius). The experimental diets were randomly allocated to a total of 48 (eight urchins per experimental group) individually cultured S. intermedius(initial weight 90.51 ± 0.82g) and the feeding period lasted for 12 weeks. The results showed that the weight gain rate of female sea urchins fed kelp was significantly higher than those fed formulated feeds while the gonadosomatic index of spawned female sea urchins fed kelp was significantly lower than those fed formulated feeds.S. intermedius broodstock fed FO showed the largest egg diameter and fecundity, which could be due to the abundant n-3 LC-PUFA deposited in the gonads of this group. Sea urchins fed SO showed the lowest fecundity and hatching rate, and the highest inflammation level. Sea urchins fed CO showed the highest content of oleic acid in the gonads and eggs, but the lowest fertilization rate. The highest hatching rate was observed in the kelp treatment, which was comparable to that in the LO and PO but was significantly higher than that in CO, FO, and SO. Before mouth opening, all prismatic larvae showed no significant differences in survival during the first 2 days post hatchery (DPH). At the 3 DPH, the survival of S. intermedius larvae was highest in the FO group, followed by those in the PO group, with the lowest survival observed in the kelp group. Thus, FO was accepted as the most ideal lipid source based on growth, reproductive performance, and early larval quality. These results could contribute to adopting an efficient feeding strategy to promote the reproductive performance and offspring quality by choosing the optimal lipid source for S. intermedius broodstock.

Effect of dietary lipid sources on rabbitfish (Siganus rivulatus) performance and health status under biofloc system condition during the nursery phase

Effect of dietary lipid sources on rabbitfish (Siganus rivulatus) performance and health status under biofloc system condition during the nursery phase

New Insight Into the Molting and Growth in Crustaceans: Regulation of Energy Homeostasis Through the Lipid Nutrition

Organisms can regulate mitochondrial metabolic adaptation, further ameliorate the energy homeostasis to control the ATP production for the energy expenditure during the growth process under different physiological and nutritional conditions. Based on this understanding, the objective of the present study was to investigate how different dietary n-3 PUFA (polyunsaturated fatty acid) lipid sources modify the mitochondrial metabolic adaptation, and further affect the energy homeostasis and the growth of swimming crab (Portunus trituberculatus). A total of 120 swimming crab juveniles with an average initial weight of 10.17 ± 0.12 g were fed one of three diets (4 replicates/treatment) containing either fish oil (control), krill oil or linseed oil as dietary lipid sources for 8 weeks, and the effects of dietary lipid sources on the growth and energy homeostasis via the regulation of mitochondrial metabolic adaptation were evaluated. The study revealed that, compared with linseed oil rich in 18:3n-3, fish oil and krill oil rich in 20:5n-3 and 22:6n-3 significantly promoted the molting and growth of juvenile swimming crab, increased the ATP level, mitochondrial membrane potential, NAD+ substrate level, NAD+/NADH ratio and the mitochondrial DNA copy number. Furthermore, crabs fed the diet supplemented with krill oil can up-regulate the expression levels of genes related to energy metabolism. In addition, dietary krill oil also specifically improved the ability for scavenging free radicals produced in the process of physiological metabolism, reduced the level of lipid peroxidation and the degree of DNA oxidative damage, and improved the health status of swimming crab. The present study revealed the adaptation of mitochondrial metabolism and the regulation of the energy homeostasis of swimming crab to different dietary n-3 PUFA lipid sources, and provided a new insight into the relationship between the growth as well as molting and the energy homeostasis, which provided a novel insight into the lipid nutrition and energy metabolism of crustacean species.

Effects of Dietary Lipid Sources on Alleviating the Negative Impacts Induced by the Fishmeal Replacement With Clostridium autoethanogenum Protein in the Diet of Pacific White Shrimp (Litopenaeus vannamei)

This study evaluated the effects of lipid sources on the replacement of fishmeal with Clostridium autoethanogenum protein (CAP) in the diet of Pacific white shrimp (Litopenaeus vannamei). By using CAP to replace 40% fishmeal in the basal diet (contains 25% fishmeal), four diets (PC as the control diet, LSO as the low soybean oil level, MSO as the middle soybean oil level, and HSO as the high soybean oil level) were formulated by adding different proportions of fish oil and soybean oil. Each diet was assigned to four replicates (40 shrimps per replicate, initial weight = 1.79 ± 0.02 g). A 7-day Vibrio parahaemolyticus challenge test was conducted at the end of the 50-day feeding experiment. Weight gain was significantly higher and the cumulative mortality after challenge was lower in HSO treatment. The total antioxidant capacity (T-AOC) in hepatopancreas was significantly raised with increasing dietary soybean oil based on CAP substitution. After challenge, Pen3 mRNA expression was significantly higher in hepatopancreas and NF-κB pathway-related mRNA (dorsal, relish, and IKKβ) expression was higher in the intestine in HSO treatment. The height of mucosal folds and the thickness of the muscle layer were positively correlated with the level of dietary soybean oil. Transmission electron microscopy (TEM) analysis showed that the microvilli were damaged and the endoplasmic reticulum was swollen in shrimp fed the LSO diet. Diversity of intestinal microbiota was increased in shrimp fed the LSO diet, with a significant increase in beneficial bacteria such as Halocynthiibacter and Ruegeria as well as less harmful bacteria such as Vibrio. These results suggested that the replacement of fishmeal with CAP and the high proportion of soybean oil in the diet could improve the growth performance, disease resistance, and intestinal structure of Pacific white shrimp, and high fish oil in a low-FM diet raised the percentage of beneficial bacteria in the intestine of shrimp.

Effects of different lipid sources on growth performance, fatty acids composition in tissue and expression of genes related to lipid metabolism in largemouth bass (Micropterus salmoides)

An eight-week feeding trial was conducted to investigate the effects of dietary lipid sources on growth performance, fatty acids composition in tissue and expression of genes related to lipid metabolism in juvenile largemouth bass (Micropterus salmoides). Four experimental diets were formulated to contain 6% coconut oil (CO), rapeseed oil (RO), linseed oil (LO) and fish oil (FO), respectively. Each diet was fed to triplicate groups of juvenile for 8 weeks. The results indicated that final body weight (FBW), percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), survival, hepatopancreas index (HSI), viscerosomatic index (VSI) and intraperitoneal fat ratio (IPF) were not significantly influenced by dietary different lipid sources (P＞0.05). Moreover, proximate composition in whole body, dorsal muscle and liver were also not significantly affected by dietary different lipid sources (P ＞0.05). Fish fed with FO diet was significantly higher MDA concentration in hepatic and serum than those fed with CO, RO and LO diets (P < 0.05). However, T-AOC, SOD and GSH activities in hepatic and serum were not affected by different lipid sources (P＞0.05). Fish fed with RO diet had significantly higher relative expression of fas and acc in liver than those fed the other diets, the highest expression of lpl was occurred at fish fed with CO diet (p < 0.05). Meanwhile, fish fed with CO and FO diets had significantly lower expression of elovl5 and Δ6fad in liver than those fed with RO diet (p < 0.05). In conclusion, the results of present study indicated that vegetable oils such as CO, RO and LO can potentially be used as dietary FO substitutes for juvenile largemouth bass.

Effects of dietary lipid sources on the growth, gonad development, nutritional and organoleptic quality, transcription of fatty acid synthesis related genes and antioxidant capacity during cold storage in adult sea urchin (Strongylocentrotus intermedius)

A 42-day feeding trial was carried out to investigate the effects of effects of five formulated feeds with different lipid sources (colza oil (CO), fish oil (FO), linseed oil (LO), soybean oil (SO), or palm oil (PO)) and kelp (Laminaria japonica) on the growth, gonad development, nutritional and organoleptic quality, transcription of fatty acid synthesis related genes, and antioxidant capacity during cold storage in adult sea urchin (Strongylocentrotus intermedius). Each diet was randomly allocated to 12 cages of sea urchins (initial weight: 60.76 ± 1.21 g). The results showed that the weight gain rate (WGR) in FO treatment was comparable to the CO and kelp, but was significantly higher than the PO, SO and LO. The WGR of S. intermedius fed SO and LO was significantly lower than that in the other dietary treatments. S. intermedius fed kelp had a significantly lower gonadosomatic index (GSI) than those fed the formulated feeds. The GSI of S. intermedius fed SO was comparable to that of sea urchins fed LO but was significantly lower than that of sea urchins fed FO, PO and CO. The percentage of gonads with market acceptable colors was highest in the PO treatment, followed by CO, FO and kelp, with the lowest value observed in SO and LO. The hardness of gonads in S. intermedius fed LO was comparable to that fed kelp, CO, and PO, but was significantly higher than that fed FO and SO. The total amino acid (AA), total sweet AA, and total umami AA were highest in the gonads of kelp treatment, which were only significantly higher than those in FO. FO contributed to the highest content of long-chain polyunsaturated fatty acids (LC-PUFAs) and ratio of EAA/TAA in the gonads. S. intermedius fed SO and LO had relatively higher ARA and EPA than the other plant oils, which could be due to the elevated transcription of fatty acid synthesis related genes. During cold storage (6–36 h), the MDA content in the gonads of S. intermedius fed FO was significantly higher than that in the other dietary treatments. In conclusion, PO and CO were most ideal lipid sources based on the growth, gonad increase and organoleptic characteristics. Although FO resulted in the highest nutritional value, it was most easily oxidized during cold storage. These results could contribute to adopting an effective and efficient feeding strategy to produce high quantity and quality gonads for adult S. intermedius.

Effect of Dietary Lipid Sources on Feed Utilization, Growth Efficiency and Carcass Composition of Clarias gariepinus Juveniles

This study was designed to investigate plant and animal lipid that can enhance feed utilization, growth, and survival of Clarias gariepinus Juveniles. Juveniles with mean weight 32.50±0.5g were stocked randomly to seven tanks replicated thrice, with each tank having seven fish each and were fed with the prepared diets with varied lipid. 40% crude protein and isocaloric diets with digestible energy of 2,933.76Kcal were formulated and labelled Diet 1-7 with different sources of plant and animal lipids. Diet 1, 2 and 3 contained palm oil, Groundnut oil and soybean oil respectively, while diet 4, 5 and 6 contained Pork lard, Cod Liver oil and Beef tallow. Diet 7 (Control diet without any lipid source).&#x0D; The result showed that there was no significant difference (P&gt;0.05) in Feed conversion ratio (FCR) and survival rates among the diets. The mean weight gain was highest in fish fed with pork lard (22.12g) while the lowest value of 15.36g was recorded in fish fed with soybean oil. Relative weight gains and feed intake showed no significant difference (P&gt;0.05) between fish fed lipids of plant origin. However, there was significant difference (P&lt;0.05) among fish fed lipids from animal origin. The Highest Total Cholesterol (28.18 mg/dl) was recorded in fish fed beef tallow as lipid sources while the least value of low-density cholesterol (value of 2.26 mg/dl) was recorded in fish fed with soybean oil. In conclusion, C. gariepinus was able to utilize animal-based lipid sources more in terms of growth and feed utilization while the lipid profile result of the individual carcass after the culture period showed that C. gariepinus fed lipid from plant sources had a slightly better cholesterol level than those fed lipid of animal sources.

Effects of dietary lipid sources on the survival, growth, body composition, antioxidant capacity and expression of antioxidant and pro‐inflammatory genes in juvenile Chinese mitten crab ( Eriocheir sinensis ) reared under three salinities

Effects of dietary lipid sources on the survival, growth, body composition, antioxidant capacity and expression of antioxidant and pro‐inflammatory genes in juvenile Chinese mitten crab ( <i>Eriocheir sinensis</i> ) reared under three salinities

Dietary lipid level and source affect metabolic responses in hybrid catfish (Pseudoplatystoma reticulatum × Leiarius marmoratus)

This study was undertaken to evaluate the effect of dietary lipid source [linseed oil (LO, rich in 18:3 n−3); corn oil (CO, rich in 18:2 n−6); olive oil (OO, rich in 18:1n−9); and fish oil (FO, rich in LC-PUFA)] and level (9% L and 18% L) on growth, body composition and selected plasma biochemistry parameters in hybrid catfish (Pseudoplatystoma reticulatum × Leiarius marmoratus) juveniles. Moreover, liver histology (lipids, glycogen, cell vacuolization) and key metabolic enzyme activities were also evaluated. After 8 weeks of feeding, there were no differences in growth performance and whole-body composition between groups. Plasma lipoprotein, muscle and liver composition, and G6PD and ME activity were affected by lipid level and source. No differences were observed between groups in hepatic ALT activity; however, AST activity was lower in fish fed the 9% L diets. Overall, liver and muscle fatty acid composition reflected that of diet FA composition, with increased n3/n6 ratio, high HUFA and low MUFA in fish fed FO compared with the VO diets. Higher liver glycogen content was observed in fish fed the 18% L than the 9% L diets, except for fish fed FO diet. Considering the experimental diets used, these results indicate that hybrid catfish can efficiently utilize VO supplementation as an energy source, without affecting growth performance and fillet composition.

Effects of dietary lipid sources on growth performance and carcass traits in Pekin ducks

This study was conducted to determine the influence of dietary lipid sources on growth performance, carcass traits and taste scores in Pekin ducks. A total of 1,500 fifteen-day-old ducks (820 ± 22 g) were blocked based on body weight (BW), and randomly allotted to 3 treatments with 10 replicates of 50 birds each (25 males and 25 females). The experiment lasted for 4 wk, and dietary treatments included 3 different lipid sources (soybean oil, duck fat, and palm oil), which were evaluated in corn-soybean meal diets (3250 kcal/kg metabolizable energy and 16.5% crude protein for grower diet and 3350 kcal/kg metabolizable energy and 15.5% crude protein for finisher diet). During days 15 to 28, feeding soybean oil and palm oil diets increased (P < 0.05) body weight gain (BWG), but decreased (P < 0.05) feed intake, feed-to-gain ratio (F/G) and caloric conversion compared with duck fat. During days 29 to 42, birds fed duck fat diet had higher BWG, but lower (P < 0.05) F/G and caloric conversion than those fed soybean oil and palm oil diets. Overall, feeding soybean oil diet increased (P < 0.05) BWG and final BW, but decreased (P < 0.05) F/G compared with palm oil. Birds fed duck fat diet had higher (P < 0.05) skin, subcutaneous fat and abdominal fat yield compared with palm oil. Left breast meat yield in soybean oil group was higher (P < 0.05) than that in duck fat and palm oil groups. Birds in soybean oil group had lower (P < 0.05) roasting loss, but higher (P < 0.05) comprehensive score compared with duck fat and palm oil. In summary, birds fed soybean oil diet had the best growth performance and taste scores for roasting, whereas the duck fat was better in abdominal fat and subcutaneous fat yield than soybean oil and palm oil in Pekin ducks from 15 to 42 d of age under the same nutritional level.

Modification of nutritional values and flavor qualities of muscle of swimming crab (Portunus trituberculatus): Application of a dietary lipid nutrition strategy

Lipid sources as alternatives to fish oil could alter the nutritional value and flavor quality of crab meat affecting consumer preferences. Herein, an 8-week nutritional trial was designed to investigate the effects of dietary lipid sources including fish oil (FO), krill oil (KO), palm oil, rapeseed oil, soybean oil and linseed oil on profiles of amino acids, fatty acids and volatiles in muscle of swimming crab (Portunus trituberculatus). Volatiles of crab muscle were characterized by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry. Results revealed that crabs fed FO and KO had significantly higher levels of protein, indispensable amino acids, eicosapentaenoic acid and docosahexaenoic acid in muscle. Principal component analysis and hierarchical cluster analysis demonstrated that muscle volatiles of crabs fed different dietary oils exhibited significant variations. Dietary FO and KO significantly increased the relative levels of 3-methylbutanal, heptanal, benzaldehyde and nonanal in muscle, which may produce more pleasant flavors.

Effects of different dietary lipid sources on growth performance, antioxidant enzyme activities and biochemical composition of juvenile swimming crab, Portunus trituberculatus

An 8-week feeding trial was conducted to evaluate the effects of dietary lipid sources on growth performance, antioxidant enzyme activities and biochemical composition of juvenile swimming crab Portunus trituberculatus of initial weight 2.34 ± 0.08 g. Four different diets were formulated to contain fish oil (FO), soybean oil (SO), linseed oil (LO) or palm oil (PO). The highest final body weight, weight gain, specific growth rate and molting frequency were observed in crabs fed the FO diet. Crabs fed the SO diet showed higher glutathione peroxidase, superoxide dismutase (SOD) and catalase (CAT) activities in both serum and hepatopancreas than those fed the FO diet. The lowest malondialdehyde concentration in hepatopancreas and serum were occurred at crabs fed the SO diet. Crabs fed the LO diet had significantly higher SOD and CAT activities in hepatopancreas compared with those fed the FO diet. Crabs fed the PO diet had the highest activities of fatty acid synthase and carnitine palmitoyltransferase 1 activities in hepatopancreas among all treatments. Fatty acid compositions both in hepatopancreas and muscle reflected those of diets. Overall, these findings demonstrated that physiological–biochemical characteristics and lipid metabolism were significantly regulated by different dietary lipid sources. Moreover, dietary SO and LO supplementation could improve antioxidant ability.

Influence of different lipid sources on growth performance, oxidation resistance and fatty acid profiles of juvenile swimming crab, Portunus trituberculatus

The effects of dietary lipid sources on growth performance, feed utilization, hematological characteristics, antioxidant capacity and tissue fatty acid profiles were assessed in juvenile swimming crab (Portunus trituberculatus). Six isonitrogenous (approximately 45% crude protein) and isolipidic (approximately 8% crude lipid) experimental diets were formulated to contain fish oil (FO), krill oil (KO), palm oil (PO), rapeseed oil (RO), soybean oil (SO) and linseed oil (LO), respectively. 270 swimming crab juveniles (approximately initial weight 5.43 ± 0.03 g) were randomly stocked and sorted into 270 individual rectangle plastic baskets in three cement pools. The results showed that crabs fed the diet containing KO had a significantly higher percent weight gain (PWG), specific growth rate (SGR) and molting ratio (MR) than those fed the other diets. Crabs fed the KO diet had the lowest feed conversion ratio (FCR) among all treatments, followed by the FO diet. However, survival, daily feed intake (DFI) and hepatosomatic index (HSI) were not affected by the dietary lipid sources. Crabs fed the FO and KO diets led to significantly higher glucose (GLU) concentration in hemolymph compared to that fed the vegetable oils (VOs) diets. Moreover, a significant elevation of total protein (TP), glucose (GLU) and low density lipoprotein (LDL) was observed in hemolymph of crabs fed the KO diet. The activities of total superoxide dismutase (T-SOD) and total antioxidant capacity (T-AOC) as well as the content of glutathione (GSH) in hepatopancreas of crabs fed the KO diet had the highest value among all treatments. The minimum concentrations of MDA in hemolymph and hepatopancreas were observed in crabs fed the KO diet. The fatty acid compositions of tissues reflected that of diets and lipid sources. Crabs fed the FO and KO diets had significantly higher values of EPA, DHA and n-3/n-6 ratio in hepatopancreas and muscle than those fed the VOs diets. In summary, based on the growth response and antioxidant capacity in comparison to VOs even FO, KO appeared to be more effective and beneficial for juvenile swimming crab. This will provide reference for the development of the diet for the reproductive and developmental stage of swimming crab.

Effects of dietary lipid sources on the intestinal microbiome and health of golden pompano (Trachinotus ovatus)

Replacement of fish oil (FO) with vegetable oils (VO) in diets is economically desirable for the sustainable development of the aquaculture industry. However, inflammation provoked by FO replacement limited its widely application in fish industry. In order to understand the mechanism of VO-induced inflammation, this study investigated the impact of different dietary vegetable oils on the intestinal health and microbiome in carnivorous marine fish golden pompano (Trachinotus ovatus). Three diets supplemented with fish oil (FO, rich in long-chain polyunsaturated fatty acids), soybean oil (SO, rich in 18:2n-6) and linseed oil (LO, rich in 18:3n-3), respectively, were fed on juvenile golden pompano for 8 weeks, and the intestinal histology, digestive enzymes activities, immunity and antioxidant indices as well as intestinal microbiome were determined. The results showed that dietary SO significantly impaired intestinal health, and decreased the number and height of intestinal folds, and muscle thickness, as well as the zonula occludens-1 (zo-1) mRNA expression in intestine. Moreover, the two dietary VO significantly decreased the amylase and lipase activities in intestine, and reduced the trypsin activity in the dietary SO group. Furthermore, the two VO diets increased intestinal acid phosphatase (ACP) activity, while intestinal lysozyme (LZM) activity and serum diamine oxidase (DAO) activity in the SO group were also significantly increased (P < 0.05). Analysis of the intestinal microbiota showed that the two VO diets significantly increased the abundance of intestinal potentially pathogenic bacteria (Mycoplasma and Vibrio) and decreased proportions of intestinal probiotics (Bacillus and Lactococcus), especially in the dietary SO group. These results indicate that complete replacement of FO with VO in diets would induce intestinal inflammation and impair intestinal function, which might be due to changes in intestinal microbiota profiles, and that dietary SO would have a more negative effect compared to dietary LO on intestinal health in T. ovatus.

Dietary lipid sources affect cold tolerance of Nile tilapia (Oreochromis niloticus)

This study was carried out to evaluate the effects of dietary lipid sources on growth performance, fatty acids composition and cold tolerance of Nile tilapia (Oreochromis niloticus) fingerlings (7.00 ± 0.50 g/fish). The fish were fed four isonitrogenous (28% crude protein), isocaloric (500 kcal/100 g) diets containing four lipid sources; fish oil (FO), corn oil (CO), coconut oil (COCO) or fish oil/ corn oil mixture (1:1 ratio) (oil mix). The diets were offered to the fish at a daily rate of 3% of their body weights (BW), twice a day for two months. After the feeding trial, the fish were exposed to decreasing water temperature from 25 °C until the appearance of death symptoms. The results revealed that FO-based diets (FO and oil mix) produced the best growth rates and feed efficiency, followed by corn oil diet, while COCO resulted in the lowest performance. Fish fed on CO and oil mix showed higher body unsaturated fatty acids (UFA) and lower lethal temperature than those fed on FO- or COCO-based diets. These results indicate that cold shock can modify the lipid metabolism in Nile tilapia by lowering total body saturated fatty acids and raising n-6 and n-3 UFA. This finding suggests that the inclusion of high levels of plant oils in Nile tilapia feeds can enhance their cold tolerance.

Effects of dietary lipid sources on hepatic nutritive contents, fatty acid composition and proteome of Nile tilapia (Oreochromis niloticus)

Dietary oils of varying fatty acid composition have been used in tilapia feeds; nevertheless, investigation of their effects on metabolism and physiological processes has been limited. Therefore, in this study, using proteomic technology, the effects of different dietary lipids (DLs) on hepatic lipid metabolism and physiological processes were investigaed in Nile tilapia (Oreochromis niloticus). Fish were fed with different DL, which included palm oil (PO), linseed oil (LO) and soybean oil (SBO) for 90 days. Growth performance appeared to be similar among the dietary group. Hepatic FA contents were reflected by DL. Dietary PO (source of saturated fatty acids; SFA) led to an increase in the hepatosomatic index as well as lipid and protein contents in liver. Dietary SBO (source of n-6 polyunsaturated fatty acids; n-6 PUFAs) increased hepatic carbohydrate contents, but decreased the hepatic protein. The proteomic analysis showed that these nutritive changes in the liver were mediated by several proteins involved in lipid, carbohydrate, and amino acid metabolism. Dietary SBO showed an increased accumulation in proteins related to oxidative stress, immune and inflammatory processes. Dietary LO (source of n-3 PUFAs) increased abundance of cytoskeleton-related proteins. qRT-PCR was performed to provide supportive information for the result of proteomic study. Similar effects of DLs on mRNA levels were observed for atp5b, krt18, and selenbp1. Combined together, dietary SFA could supply as energy reservoir for regular activites. Dietary n-3 and n-6 PUFAs led to induce vital metabolic and physiologic processes which would contribute to maintaining normal health and/or providing health-related benefits. SignificanceDietary SBO increased hepatic carbohydrate contents, but decreased the hepatic protein. Different dietary lipid led to alter the abundance of several proteins (i.e., DHRS1, ATP5B, PLA2G12B, APO, AMY2A, GRP78, PRSS1, FAH, and PRSS36) involved in lipid, carbohydrate, and amino acid metabolism. Dietary SBO showed an increased accumulation in proteins (i.e., QDPR, CABC1, and PRDX6) that respond to oxidative stress, suggesting that n-6 PUFAs induce oxidative conditions. Dietary SBO led to increase the accumulation of proteins (i.e., NITR26, NCCRP1, and LCN) involved in immune and inflammatory processes. Dietary LO increased the abundant levels of cytoskeleton-related proteins (i.e., ACTB, AHNAK, ERC2, KRT18, and RILP1). Other proteins (i.e., SELENBP1, FAM46C, and ANC1) involved in other physiological processes were also modulated by DL. qRT-PCR was performed to provide supportive information of proteomic study. Similar effects of DLs on mRNA levels were observed for atp5b, krt18, and selenbp1.

Effects of dietary lipid sources on growth performance, fatty acid composition and hepatic lipid metabolism of juvenile blunt snout bream, Megalobrama amblycephala

This study investigated the effects of dietary lipid sources on juvenile blunt snout bream, Megalobrama amblycephala. Juvenile blunt snout bream (14.40 ± 0.01 g) were fed diets containing 75 g/kg of fish oil (FO), linseed oil (LO), soybean oil, coconut oil (CO), rapeseed oil or beef tallow (BT) for 9 weeks. Survival rates, final weight, weight gain, feed efficiency ratio and feed intake remained unchanged. Viscerosomatic ratio, hepatosomatic index and condition factor were highest in fish fed the CO diet (p < 0.05). Whole‐body lipid content decreased, whereas liver lipid content increased in fish fed CO and BT diets (p < 0.05). Eicosapentaenoic acid and docosahexaenoic acid in the muscle and liver increased in fish fed the FO and LO diets (p < 0.05). FO and LO diets increased plasma glucose (p < 0.05). Feeding CO diet increased hepatic fatty acid synthase (FAS) and acetyl‐CoA carboxylase expression, and FAS activity (p < 0.05). Both CO and BT diets increased hepatic carnitine palmitoyltransferase I (CPT I) and carnitine palmitoyltransferase II expression, and CPT I activity compared to the FO diet (p < 0.05). These results indicate that LO can be substituted for FO in juvenile blunt snout bream diets without negative effects.

On growth performance, nutrient digestibility, blood T lymphocyte subsets, and cardiac antioxidant status of broilers.

Different lipid sources differ in the fatty acid profiles and differently affect growth performance as well as immune function of broilers. The influences of different dietary lipid sources on growth performance, nutrient digestibility, blood T lymphocyte population, and cardiac antioxidant status were investigated of broilers. A total of 360 one-day-old male broilers (BW = 44 ± 3 g) were randomized into 3 treatment groups, consisting of 6 replicates with 20 birds in each group. Broilers received standard diets supplemented with 5% (wt/wt) of lard (LD, as a control diet), sesame oil (SO), or flaxseed oil (FO). Broilers in both SO and FO treatment groups had lower (P < 0.05) feed conversion ratios from 22 to 42 d and during the overall phase compared to those in LD treatment group. Meanwhile, the apparent total tract nutrient digestibility of crude fat in SO and FO treatment groups was higher than that in LD treatment group. Both FO and SO treatments decreased (P < 0.05) abdominal fat percentage compared to LD treatment. Total triglycerides and total cholesterol in chicken blood were decreased (P < 0.05) by SO and FO treatments compared to LD treatment. Feeding broilers with FO and SO led to a decrease (P < 0.05) in blood CD4+ T lymphocyte count and in CD4+:CD8+ ratio compared to LD treatment. Sesame oil and FO treatments increased cardiac glutathione peroxidase (P < 0.05) compared to LD treatment. It is concluded that addition of 5% SO and FO to the standard corn-soybean meal diet improved feed efficiency, increased the activities of cardiac glutathione peroxidase, and affected the T lymphocytes ratio of fast growing broilers.