Dietary Lipid Sources Research Articles

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 iron-deficient diets during gestation and lactation on cerebral fatty acids and eicosanoids in guinea pig offspring—Comparison of studies with different sources of dietary lipids

Previous studies showed that mild iron deficiency anaemia (IDA) induced by feeding an iron deficient (ID) diet to female guinea pigs during gestation and lactation to alters the auditory functions of the offspring when corn oil is the only source of dietary lipids. Conversely, feeding an ID diet with a dietary fatty acid composition similar to that of typical human western diets induced minor impairments. Since tissue fatty acid metabolism is affected by dietary iron, the current study measured the impacts of these ID diets (ID-corn and ID-west) compared to the corresponding iron-sufficient control diets (IS-corn and IS-west) on encephalum fatty acid metabolism in the offspring at post-natal day 24. IDA induced by the ID-corn diet resulted in significant increases in encephalum n-6 PUFA content, but IDA induced by the ID-west diet had little impact on fatty acid profiles compared to the IS-west group. Brain COX II protein expression and FADS2 mRNA expression were statistically unaffected in both experiments, but encephalum PGE2 concentrations were significantly reduced in ID-west pups. These results suggest IDA studies during prenatal development should consider dietary lipid compositions.

162 The interactions between dietary fiber and lipid sources alter the predicted production and absorption of caecal and colorectal volatile fatty acids in growing pigs

Abstract A combination of in vivo and in vitro fermentation methodologies was used to determine the interactive effects of dietary fiber (DF) and lipid types on volatile fatty acids (VFA) production and absorption, and organic matter (OM) fermentability in the cecum and colorectal tract of pigs. Eight ileal- and caecal-cannulated Yorkshire barrows were fed either pectin- or cellulose-containing diets that were supplemented with either corn oil or beef tallow in two independent Youden squares with a 2×2 factorial arrangement of treatments (n = 6). Ileal and caecal digesta were collected, freeze-dried and fermented using inoculum from fresh caecal digesta and feces, respectively, to determine VFA production and absorption, and fermentability of OM. There were interactions (P < 0.001) between DF and lipid types observed in which the addition of corn oil increased the quantity of caecal and colorectal acetic acid production and caecal acetic absorption, caecal butyric production, predicted caecal OM fermentability, and the predicted colorectal propionic acid in pectin diets but did not have effects in cellulose diets. The addition of beef tallow increased (P < 0.001) the production of caecal butyric and propionic acids during in vitro fermentation in cellulose diets and fermentability of OM in pectin diets. The interactions between DF and lipids on gastrointestinal fermentation largely depends on the degree of saturation of fatty acids in dietary lipids. The addition of beef tallow selectively decreased the production and absorption of individual SCFA in pectin and cellulose diets but increased caecal butyric and propionic acid production in cellulose diets and the fermentability of OM in pectin diets.

Molecular cloning, functional characterization and nutritional regulation of two elovl4b elongases from rainbow trout (Oncorhynchus mykiss)

Elongation of very long-chain fatty acids 4 (Elovl4) is a critical enzyme in the biosynthesis of long-chain and very long-chain polyunsaturated fatty acids (LC- and VLC-PUFAs) in animals. So far, very little is known about the molecular function of Elovl4 in biosynthetic process, especially in fish. In this study, two elovl4 paralogs (elovl4b1 and elovl4b2) were successfully cloned from rainbow trout (Oncorhynchus mykiss). The full-length cDNAs of elovl4b1 and elovl4b2 were shown to comprise 1896 bp and 2227 bp, respectively, and both contained 921 bp open reading frames (ORFs), encoded 306 amino acids in high homology. Heterologous expression in yeast showed that rainbow trout Elovl4b1 and Elovl4b2 proteins are able to effectively convert C18-22 polyunsaturated fatty acids (PUFAs) to the polyenoic products up to C32 or C36. Especially, compared with Elovl4b2, Elovl4b1 had much higher efficiency for converting 20:5n-3 and 22:5n-3 to 24:5n-3. Tissue distribution analysis revealed that rainbow trout elovl4b were widely transcribed in various tissues with the highest level in eye, brain and gill. Feeding experiment was conducted with three groups of rainbow trout fed diets with either fish oil (FO) or 100% of the FO replaced by soybean oil (SO) and linseeds oil (LO). Compared to fish fed the diet with FO, elovl4b was significantly up-regulated in the liver of fish fed the diet with SO and in the entire intestine of fish fed the diet with LO, which suggested that elovl4b expression is regulated by dietary lipid sources. These results may contribute to better understand the LC-PUFAs and VLC-PUFAs biosynthetic pathway and the regulation mechanism in rainbow trout.

Triacylglycerols fingerprint of edible vegetable oils by ultra-performance liquid chromatography-Q-ToF-MS

Triacylglycerols (TAGs) are an important source of dietary lipids that constitute an essential part of a healthy diet. The TAG profiles of vegetable oils are not arbitrary, and they are recently reported to be associated with lipid absorption and metabolism. In the present study, the TAG composition, FA composition, and their distributions in 18 commonly edible vegetable oils were analyzed and compared. The TAGs were quantified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (Q-ToF-MS). A total of 48 TAGs were identified. The composition of FAs and their distribution on the glycerol backbone of vegetable oils were determined by gas chromatography. The TAG compositions of different types of vegetable oils were found to be significantly different. Unique patterns of the TAG profiles of vegetable oils were obtained. Linoleic acid showed a clear difference between the total fatty acid and sn-2 position of the TAGs. This study will aid the investigation of the association of TAGs in dietary lipid and human health, and the development of novel lipid-based matrixes.

Effect of dietary inclusion of different lipid supplements on performance and carcass quality traits of growing beef heifers.

The aim of this study was to evaluate the impact of dietary extruded flaxseed and/or rumen-protected lipids on growth performance and carcass quality of growing beef heifers. Sixty-three crossbreed heifers (Charolais X Limousine) were distributed into seven experimental groups, balanced in terms of age and live weight. Diets fed to the groups were isoproteic and differed in both, the dietary lipid source (extruded linseed and/or rumen-protected conjugated linoleic acid) and the supplementation length (90 or 180 days before slaughtering), having the same total amount of lipids and vitamin E, during their finishing period. The results obtained in the present study confirm that in low-protein diets, the inclusion of rumen-protected CLA, alone or in combination with flaxseed, did not bring any evident effect on feed intake, performance and carcass quality traits of growing beef heifers.

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.

Regulation of Dietary Lipid Sources on Tissue Lipid Classes and Mitochondrial Energy Metabolism of Juvenile Swimming Crab, Portunus trituberculatus.

An 8-weeks feeding trial with swimming crab, Portunus trituberculatus, was conducted to investigate the effects of different dietary lipid sources on the lipid classes, lipid metabolism, and mitochondrial energy metabolism relevant genes expression. Six isonitrogenous and isolipidic 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. A total of 270 swimming crab juveniles (initial weight 5.43 ± 0.03 g) were randomly divided into six diets with three replications, each consisted of 45 juvenile crabs. The results revealed that crabs fed KO had highest lipid content in hepatopancreas and free fatty acids in serum among all diets. The anabolic pathway relevant genes: fas and acc were up-regulated in KO diet. The catabolic pathway relevant genes, hsl, was up-regulated in LO diet, while cpt1 was up-regulated in KO diet. Whereas, the genes involved in the transport and uptake of fatty acids such as fabp1 and fatp4 were down-regulated in crab fed PO and RO diets. Furthermore, the gene expression levels of transcription factors: srebp-1 and hnf4α in KO and SO diets were the highest among all diets. FO and KO diets had significantly higher unsaturation index of mitochondrial membrane than others. The genes related to mitochondrial energy metabolism, such as Atpase6, sirt1, and sirt3 were significantly up-regulated in KO and SO diets. In summary, dietary KO and SO supplementation could improve the lipid metabolism, promote energy production for juvenile swimming crab and improve physiological process and function including molting. These findings could contribute to deepen the understanding of the physiological metabolism of dietary fatty acids for swimming crab.

Characterisation of several types of millets as functional food ingredients

Millets can be sustainable food sources in future agronomy because of its ability to flourish in harsh climatic conditions, however limited studies exist on the nutritional and hypoglycaemic properties of millets. This study is intended to identify millets as potential functional food ingredients based on their nutrient profile and in vitro starch digestibility. Seven millet types exhibiting diverse structures and compositions were investigated. Chemical composition revealed that depending on the millet type, millets are excellent sources of insoluble dietary fibre, lipids and minerals, these components had values ranging from 9.3–56.7 mg/g, 11.5–31.7% and 2.1–8.0%, respectively. Linoleic and oleic were the major unsaturated fatty acids detected in all the millet types. Millets were also found to be rich in free and bound phenolic acids. Kodo millet was found to have the highest free and bound phenolic contents. Expected glycemic index of millets ranged between 42.7 and 58.3, hence making them some valuable low GI food sources for diabetics. The obtained results may suggest that millets with its superior nutrient profile and hypoglycaemic property could be a promising ingredient for the functional food industry.

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.

SOURCES OF LIPIDS IN DIETS FOR SILVER CATFISH (Rhamdia quelen) JUVENILES

The purpose of this study was to evaluate different lipid sources in diets for silver catfish juveniles regarding aspects of productive performance, centesimal composition, hepatic histology, biochemical responses, and oxidative stress. A total of 300 juveniles with an initial mean weight of 18.45 ± 1.22g were distributed in 20 net-pens of 1m3, arranged in a 200 m2 masonry tank, for a period of 90 days. The experimental diets were isoprotein (29.05% digestible protein) and isoenergetic (3,250 kcal.kg-1), containing different sources of oils (soybean, sunflower, fish, canola and olive) at a concentration of 3.0%. The animals were distributed in a completely randomized design, with five treatments and four replicates. The data were submitted to ANOVA, and the means, when significant, were compared by the Tukey test at 5% significance level. Visceral fat index was higher for fish fed diets containing sunflower oil (P&lt;0.05). No differences (P&gt;0.05) were observed for the variables of productive performance, centesimal composition, and blood biochemistry. A difference (P&lt;0.05) was observed in hepatic histology, where the treatment with soybean oil had a higher number of hepatocytes. The animals fed with fish oil had a higher TBARS lipid peroxidation and a higher GST enzyme activity (P&lt;0.05). Therefore, the different lipid sources can be used to feed this species without any damage to productive performance. It is not advisable to include sunflower oil, as it provides greater deposition of visceral fat.

Edible caterpillars of Imbrasia truncata and Imbrasia epimethea contain lipids and proteins of high potential for nutrition

Imbrasia truncata and I. epimethea caterpillars were evaluated as dietary protein and lipid sources. They contained approximately 7.0 g/100 g fresh weight (FW) of lipids and 20.0 g/100 g FW of proteins calculed with determined nitrogen to protein conversion factors: 6.01 ± 0.21 and 6.27 ± 0.15 for I. truncata and I. epimethea, respectively. Unsaturated fatty acids represented about 2.63 ± 0.21 g/100 g FW for I. truncata and 3.24 ± 0.21 g/100 g FW for I. epimethea, with α-linolenic acid as major fatty acid (around 1.88 ± 0.15 g/100 g FW for I. truncata 2.17 ± 0.13 g/100 g FW for I. epimethea) and very low n-6/n-3 ratios: 0.15 (I. truncata) and 0.27 (I. epimethea). Polar lipids (phospholipids and glycolipids + sulfolipids), representing between 4 and 6% of lipids, contained little amounts of arachidonic acid (C20:4n-6). The major tocopherol isomer was α−tocopherol in I. truncata (0.52 ± 0.08 g/100 g FW) and γ−tocopherol in I. epimethea (1.00 ± 0.08 g/100 g FW). The proteins of both insect included all indispensable amino acids at amounts (mg/g protein) higher than the indispensable amino acid requirement patterns recommended by WHO/FAO/UNU (2007). In conclusion, Imbrasia caterpillars exhibit a great nutritional potential due to the presence of good quality proteins and healthy fat

Effects of breed and different lipid dietary supplements on beef quality.

Focus of this study was to evaluate the most suitable breed/crossbred and the appropriate nutritional strategies to increase marbling in beef muscle and to improve its healthy properties, in particular the n-3 fatty acids content. One hundred and seventy-six heifers of three crossbreed commonly reared by Emilia-Romagna farmers: 48 Bleu Belge×Freisian (ITA), 48 Charolais×Aubrac (FRA), and 80 Angus (ANG) were used. Animals of each breed were randomly subdivided in two experimental groups that received two diets, differing for the dietary lipid source. Control group (C) received a basal diet containing protected vegetable fats, whereas treated one (T) received the same basal diet supplemented with 0.9kg/head/day of extruded flaxseed. After slaughtering, a sample of Longissimus thoracis was collected from each animal for meat quality analysis. Our results demonstrated that, in a shorter fattening period, ANG animals obtained the best dry matter intake, average daily gain and the best fattening scores. ITA and ANG meat presented the highest marbling scores. ANG breed had the highest amount of C18:1, the highest unsaturated/saturated fatty acids ratio and the lowest n-6/n-3 ratio. The T animals, independently from breed, showed the highest amount of α-linolenic acid (ALA). In addition, ANG-T meat presented the highest ALA content.

Assessing the feasibility of using pomegranate (Punica granatum) seed oil, rich in conjugated linolenic acid, as a lipid source in the diet of common carp,Cyprinus carpio, juveniles

In this study, the feasibility of using pomegranate seed oil, rich in conjugated linolenic acid and its partial replacement for fish oil in fish diet were investigated. Common carp, Cyprinus carpio, juveniles (1.8 ± 0.1 g) were fed four isonitrogenous and isolipidic diets with similar basal composition but different oil mixture containing 100% fish oil (A), 50% fish oil +50% sunflower oil (B), 50% fish oil +25% sunflower oil +25% pomegranate seed oil (C) and 50% fish oil +50% pomegranate seed oil (D) for 8 weeks. The highest weight gain was observed in fish fed diet D (p < 0.05). Test diets had no significant effect (p > 0.05) on saturated and monounsaturated fatty acid contents of fish muscle. Docosahexaenoic acid (22:6n-3; DHA) was significantly lower in the muscle of fish fed diet B (p < 0.05) compared to those fed diet A. However, there was no significant difference in the muscle DHA content of fish fed diets A, C, or D. No specific hepatocyte damage associated to dietary pomegranate seed oil was found in this study. This study showed a 50-50 combination of fish oil and pomegranate seed oil could be used as dietary lipid source for common carp without any adverse effect on growth performance or muscle n-3 content while accumulated punicic acid in the muscle could be considered as added value for the final human consumer.

Potential of Corn Oil as Alternative Dietary Lipid Source in Aquaculture Feeds

Potential of Corn Oil as Alternative Dietary Lipid Source in Aquaculture Feeds

Effects of fish oil replacement with vegetable oil in diet of sterlet sturgeon (Acipenser ruthenus) broodstock on expression of lipid metabolism related genes in eggs

A 7-month feeding trial was conducted before spawning induction in sterlet (Acipenser ruthenus) broodstock (initial weight 990.3 ± 20.05 g). The effects of dietary fish and vegetable oils were investigated on fatty acid profiles in eggs, hematological characteristics, serum lipid indices, and expression of some lipid metabolism and transport-related genes. Three experimental diets with different levels of fish and vegetable oils were formulated as: FO (100% kilka oil), VO (100% rapeseed oil), and FO + VO (50% kilka oil + 50% rapeseed oil). At the end of the feeding trial, egg samples from ovulating females were collected to examine fatty acid profiles and transcriptional mechanisms involved in lipid metabolism and transport. The broodstock physiological condition was assessed using hematological and biochemical indices. Similar to the diets, oleic acid (18:1n-9) was the most predominant monounsaturated fatty acid among all lipid classes in sterlet eggs. Results revealed that the eggs of the broodstock fed VO diet had the highest ratio of DHA/EPA, while the eggs of the broodstock fed FO + VO or FO diet showed higher ratios of EPA/ARA and DHA/ARA. No changes were observed in the levels of lipoproteins, blood lipid indices or hematological parameters in broodstock. This implies that the examined oil sources did not have any adverse effects on fish health during the feeding trial. Feeding different dietary ratios of VO and FO resulted in altered expression of ApoE and PPARα in the eggs, suggesting that lipid metabolism pathways can be influenced by dietary lipid sources. Compared with broodstock fed FO or FO + VO diet, in eggs from the broodstock fed VO diet the expression of ApoE gene was significantly up-regulated and the expression of PPARα was down-regulated. However, the expression of PPARγ was not significantly different among the dietary treatments. Different expression levels of related genes in treatment with various oil sources demonstrate that ApoE, PPARα, and PPARγ play key roles in lipid metabolism, such that they might perform different functions in lipid metabolism and utilization.

Lipid Sources in Diets for Hy-Line White Laying: Performance, Biometrics of Digestive Organs, and Bone Characteristics

ABSTRACT Dietary inclusion of lipid sources has been one of the methods adopted by nutritionists aiming at better energy balancing. However, alternative energy feedstuffs have been sought in an attempt to reduce production costs. In this regard, lipid sources that can replace conventional ones, such as beef tallow, cottonseed oil, and sunflower oil have been investigated. The objective of this study was to examine the effects of different lipid sources on the performance, egg quality, biometrics of digestive organs, and bone quality of white-egg commercial layers in the first production cycle. A total of 216 Hy-Line White layers at 70 weeks of age, weighing 1.701 ± 0.103 kg, were used in a completely randomized design with four treatments and six replicates. The diets provided to them contained equal amounts of protein, calories, and amino acids, with only the lipid source varying - soybean oil (control), cottonseed oil, beef tallow, and sunflower oil. No significant effect of lipid sources was observed on any of the performance or egg-quality variables assessed (p>0.05). Biometric variables were not influenced by lipid sources, except for abdominal fat, which was highest in the birds receiving the beef-tallow treatments and lowest in birds fed the sunflower-oil diets (p<0.05). Except for mineral matter, bone traits were not influenced by the treatments; this variable was highest in the control treatments and lowest in the beef-tallow treatments. In conclusion, cottonseed and sunflower oils can be used to fully replace soybean oil in diets for white-egg commercial layers.

Diet and nutritional status during early adult life have immediate and persistent effects on queen bumble bees.

Many insects sequester nutrients during developmentally programmed periods, which they metabolize during subsequent life history stages. During these periods, failure to store adequate nutrients can have persistent effects on fitness. Here, we examined a critical but under-studied nutrient storage period in queen bumble bees: the first days of adult life, which are followed by a diapause period typically coinciding with winter. We experimentally manipulated availability of pollen (the primary dietary source of lipids and protein) and the sugar concentration of artificial nectar (the primary source of carbohydrates) for laboratory-reared queens during this period and examined three nutritional phenomena: (i) diet impacts on nutritional status, (ii) the timescale upon which nutrient sequestration occurs and (iii) the fitness consequences of nutrient sequestration, specifically related to survival across the life cycle. We found evidence that pollen and nectar starvation negatively impact lipid storage, whereas nectar sugar concentration impacts stored carbohydrates. The majority of nutrients were stored during the first ~ 3days of adult life. Nutrients derived from pollen during this period appear to be more critical for surviving earlier life stages, whereas nutrients sequestered from nectar become more important for surviving the diapause and post-diapause periods. Negative impacts of a poor diet during early life persisted in our experiment, even when pollen and a relatively high (50%) nectar sugar concentration were provided post-diapause. Based on these findings, we posit that the nutritional environment during the early adult life of queens has both immediate and persistent impacts on fitness. These findings underscore the importance of examining effects of stage-specific nutritional limitations on physiology and life history traits in this social insect group. Moreover, the findings may shed light on how declining food resources are contributing to the decline of wild bumble bee populations.

Partial and total replacement of fish oil by poultry fat in diets for European seabass (Dicentrarchus labrax) juveniles: Effects on nutrient utilization, growth performance, tissue composition and lipid metabolism

Rendered fats can be sustainable alternatives to fish oil due to their lower price and wider availability. This study evaluates the effects of replacing fish oil by increasing levels of poultry fat (PF) on the nutrient utilization, growth performance, tissue composition and lipid metabolism of European seabass (Dicentrarchus labrax) juveniles. Homogeneous groups of 20 fish (19.1 ± 2.6 g) were subjected to a 12-h light/12-h dark photoperiod regime and kept in a recirculating saltwater system (salinity 35‰, 21 ± 1 °C) for 16 weeks. Triplicate groups of fish were fed a commercial-based diet as control (FO) and four isonitrogenous experimental diets, with 25 (25PF), 50 (50PF), 75 (75PF) and 100% (100PF) fish oil replacement. Soy lecithin was also tested in the diet with 100% PF (100PFL) as an emulsifier agent. The inclusion of PF did not affect nutrient's digestibility nor plasma metabolites at 24 h post-feeding. Final body weight (62–67 g), feed intake, feed conversion ratio, protein efficiency ratio and whole-body composition were similar among experimental diets. Selected lipogenic enzymes' activities were similar among FO and PF diets. The fatty acids profile of muscle, liver and heart reflected the dietary lipid source, decreasing PUFA and increasing MUFA contents with PF inclusion. Fish fed 25PF and 50PF were still able to provide the EPA and DHA muscle levels recommended for human consumption, but 100PF resulted in increased liver lipid accumulation and reduced muscle omega-3 levels. Including soy lecithin could significantly attenuate liver lipid content in fish fed PF-based diets.

Performance, fatty acids profile and oxidative stability of meat of rabbits fed different lipid sources

Abstract To evaluate the use of different lipid sources in diets of growing rabbits, 60 New Zealand White rabbits were evaluated on performance, carcass traits, meat composition, fatty acid profile and oxidative stability of refrigerated and frozen meat. The experiment was distributed in a randomized block design, in five treatments, with six replicates and two animals per experimental unit (one male and one female). The treatments consisted of five isonutritive diets, with 2.5% soybean oil (SO), sunflower oil (SFO), cottonseed oil (CO), beef tallow (BT) and poultry fat (PF). There was no effect (P > 0.05) of dietary lipid sources on animal performance, carcass traits and meat composition (P > 0.05). Dietary inclusion of beef tallow resulted in a lower proportion of polyunsaturated fatty acids in meat compared to vegetable oils. The values of thiobarbituric acid-reactive substances (TBARS) indicated higher oxidation in the frozen meat of the animals fed with sunflower oil, cottonseed oil and bovine tallow in their diets. In conclusion, vegetable oils and animal fats can be included in growing rabbit diets without impair performance and meat quality parameters. Dietary inclusion of soybean oil is more advantageous because it promotes the incorporation of polyunsaturated fatty acids and greater lipid stability of refrigerated and frozen rabbit meat.