Effects of long-term microalgae supplementation on muscle microstructure, meat quality and fatty acid composition in growing pigs

Replacing Soybean Meal with Hemp Leaves in a Dairy Cow Diet: Plasma Antioxidative Capacity, Inflammatory Parameters and Milk Constituents

Hemp is rich in bioactive compounds known to exert antioxidant and anti-inflammatory properties. We hypothesised that feeding industrial hemp leaves would increase the antioxidative capacity, reduce pro-inflammatory markers, and modulate the milk amino and fatty acid profiles of dairy cows. Twelve Holstein dairy cows were randomly assigned to a total mixed ration (TMR) containing 7.4% industrial hemp leaves (HEMP) of the Santhica 27 variety or a TMR-based diet containing 3.5% soybean meal (CON). Diets were fed in a cross-over design, each for 2 weeks divided by a 2-week washout period. HEMP cows revealed higher plasma and milk cannabinoid concentrations, plasma antioxidative capacity and anserine concentration, but lower plasma π-methylhistidine, α-aminoadipic acid and isoleucine concentrations. Lipid peroxidation and tumour necrosis factor-alpha concentrations were not different between groups. The leukocyte RELA mRNA expression was higher, whereas the TNFA mRNA abundance tended to be lower in the HEMP group. In milk, n-3 polyunsaturated fatty acid (PUFA) concentrations were higher, and the n-6/n-3 PUFA ratio was lower in HEMP than in CON cows. The results provide evidence that the supplementation with Santhica 27 hemp leaves increases the antioxidative capacity of dairy cows and results in a transfer of cannabinoids into milk.

Effects of n-3 polyunsaturated fatty acids and selenomethionine supplementation on physicochemical properties, oxidative stability and endogenous enzyme activities of fresh pork loin

This study evaluated the physicochemical properties, oxidative stability, and endogenous enzyme activities in fresh pork loin from pigs fattened by supplementation of 3 % soybean oil (control), 3 % linseed oil or 3 % linseed oil combined with 0.3 mg/kg selenomethionine (SeMet). Both linseed oil treatments led to higher n-3 polyunsaturated fatty acids (PUFA) levels, lower L* values, n-6/n-3 ratios, and lipoxygenase activity compared to the control (P < 0.001). Supplementation with linseed oil alone reduced a*, n-6 PUFA, saturated and monounsaturated fatty acids, and GPx activity in pork loin compared to other treatments (P < 0.05). Adding SeMet decreased neutral lipase activity but did not affect a* or GPx activity (P > 0.05), likely due to the antioxidant property of SeMet. Overall, linseed oil and SeMet supplementation is a promising strategy to significantly increase n-3 PUFA content in pork without compromising color properties or oxidative stability.

An Integrated Profiling of Liver Metabolome and Transcriptome of Pigs Fed Diets with Different Starch Sources

Diets containing higher-amylose-content starches were proved to have some beneficial effects on monogastric animals, such as promoting the proliferation of intestinal probiotics. However, current research on the effects of diets with different starch sources on animals at the extraintestinal level is still very limited. We hypothesized that diets with different starch sources may affect lipid-related gene expression and metabolism in the liver of pigs. This study aimed to use adult pig models to evaluate the effects of diets with different starch sources (tapioca starch, TS; pea starch, PS) on the liver gene expressions and metabolism. In total, 48 growing pigs were randomly assigned to the TS and PS diets with 8 replicate pens/group and 3 pigs per pen. On day 44 of the experiment, liver samples were collected for metabolome and transcriptome analysis. Metabolome data suggested that different starch sources affected (p < 0.05) the metabolic patterns of liver. Compared with the TS diet, the PS diet increased (p < 0.05) some unsaturated fatty acids and several amino acids or peptide levels in the liver of pigs. Moreover, transcriptome data indicated the PS diets elevated (p < 0.05) fatty acid β-oxidation-related gene expression in the liver of pigs, and reduced (p < 0.05) unsaturated fatty acid metabolism-related gene expression. The results of quantitative real-time PCR confirmed that the PS diet upregulated (p < 0.05) the expression of acyl-CoA dehydrogenase very long chain (ACADVL), carnitine palmitoyl transferase (CPT) 1A, and malonyl-CoA decarboxylase (MLYCD), and downregulated (p < 0.05) the expression level of cytochrome P450 2U1 (CYP2U1) and aldehyde dehydrogenase 1B1 (ALDH1B1) in the liver. In addition, the results of a Mantel test indicated the muscle fatty acids were significantly closely correlated (p < 0.05) with liver gene expressions and metabolites. In summary, these findings suggest that diets containing higher amylose starches improved the lipid degradation and the unsaturated fatty acid levels in pig livers, and thus can generate some potential beneficial effects (such as anti-inflammatory and antioxidant) on pig health.

Metabolomics and proteomics insights into hepatic responses of weaned piglets to dietary Spirulina inclusion and lysozyme supplementation

BACKGROUND

Studying the effect of dietary Spirulina and lysozyme supplementation on the metabolome and proteome of liver tissue contributes to understanding potential hepatic adaptations of piglets to these novel diets. This study aimed to understand the influence of including 10% Spirulina on the metabolome and proteome of piglet liver tissue. Three groups of 10 post-weaned piglets, housed in pairs, were fed for 28 days with one of three experimental diets: a cereal and soybean meal-based diet (Control), a base diet with 10% Spirulina (SP), and an SP diet supplemented with 0.01% lysozyme (SP + L). At the end of the trial, animals were sacrificed and liver tissue was collected. Metabolomics analysis (n = 10) was performed using NMR data analysed with PCA and PLS-DA. Proteomics analysis (n = 5) was conducted using a filter aided sample preparation (FASP) protocol and Tandem Mass Tag (TMT)-based quantitative approach with an Orbitrap mass spectrometer.

RESULTS

Growth performance showed an average daily gain reduction of 9.5% and a feed conversion ratio increase of 10.6% in groups fed Spirulina compared to the control group. Metabolomic analysis revealed no significant differences among the groups and identified 60 metabolites in the liver tissue. Proteomics analysis identified 2,560 proteins, with 132, 11, and 52 differentially expressed in the Control vs. SP, Control vs. SP + L and SP vs. SP + L comparisons, respectively. This study demonstrated that Spirulina enhances liver energy conversion efficiency, detoxification and cellular secretion. It improves hepatic metabolic efficiency through alterations in fatty acid oxidation (e.g., upregulation of enzymes like fatty acid synthase and increased acetyl-CoA levels), carbohydrate catabolism (e.g., increased glucose and glucose-6-phosphate), pyruvate metabolism (e.g., higher levels of pyruvate and phosphoenolpyruvate carboxykinase), and cellular defence mechanisms (e.g., upregulation of glutathione and metallothionein). Lysozyme supplementation mitigates some adverse effects of Spirulina, bringing physiological responses closer to control levels. This includes fewer differentially expressed proteins and improved dry matter, organic matter and energy digestibility. Lysozyme also enhances coenzyme availability, skeletal myofibril assembly, actin-mediated cell contraction, tissue regeneration and development through mesenchymal migration and nucleic acid synthesis pathways.

CONCLUSIONS

While Spirulina inclusion had some adverse effects on growth performance, it also enhanced hepatic metabolic efficiency by improving fatty acid oxidation, carbohydrate catabolism and cellular defence mechanisms. The addition of lysozyme further improved these benefits by reducing some of the negative impacts on growth and enhancing nutrient digestibility, tissue regeneration, and overall metabolic balance. Together, Spirulina and lysozyme demonstrate potential as functional dietary components, but further optimization is needed to fully realize their benefits without compromising growth performance.

Principles, challenges, and optimization of indigenous microalgae-bacteria consortium for sustainable swine wastewater treatment

Indigenous microalgae-bacteria consortium (IMBC) offers significant advantages for swine wastewater (SW) treatment including enhanced adaptability and resource recovery. In this review, the approaches for enriching IMBC both in situ and ex situ were comprehensively described, followed by symbiotic mechanisms for IMBC which involve metabolic cross-feeding and signal transmission. Strategies for enhancing treatment efficiencies of SW-originated IMBC were then introduced, including improving SW quality, optimizing system operating conditions, and adjusting microbial activities. Recommendations for maximizing treatment efficiencies were particularly proposed using a decision tree approach. Moreover, removal/recovery mechanisms for typical pollutants in SW using IMBC were critically discussed. Ultimately, a technical route termed SW-IMBC-Crop-Pig was proposed, to achieve a closed-loop economy for pig farms by integrating SW treatment with crop cultivation. This review provides a deeper understanding of the mechanism and strategies for IMBC's resource recovery from SW.

The comparison of meat yield, quality, and flavor between small-tailed Han sheep and two crossbred sheep and the verification of related candidate genes

Introduction

In Northeast China, Dorper and Australian White rams are commonly crossbred with small-tailed Han (STH) ewes to improve the offspring's meat yield and quality. However, the differences in traits and the flavor between the crossbred sheep and STH sheep remain unclear. In addition, the candidate genes potentially influencing the meat quality in the three sheep breeds require further verification.

Methods

A total of 18 2-month-old healthy rams were raised over a period of 5 months, which included 6 STH, 6 Dorper and small-tailed Han crossbred (Do × STH), and 6 Australian white and small-tailed Han crossbred (Au × STH) offspring. The differences in slaughter, meat quality traits, fatty acid and amino acid composition in the muscular longissimus dorsi (MLD), and volatile compounds in the semitendinosus muscle were compared between the sheep breeds. The candidate genes related to intramuscular fat (IMF) content and fatty acids were validated.

Results

The results of this study revealed that the crossbred sheep had higher body weight, carcass weight, bone weight, net meat weight, and IMF content than the STH sheep (p < 0.05). The Do × STH offspring had a higher pH value (24 h), moisture content, and cooking percentage; they also had redder and brighter meat color. The content of myristate, palmitic, and margaric acids in the crossbred sheep was higher than that in the STH sheep (p < 0.05). The Do × STH offspring had the highest saturated fatty acid content (p < 0.05). The Au × STH offspring had the highest protein content (p < 0.05). The arachidonic acid and amino acid (Asp, Ala, Ile, Leu, Lys, Thr, and essential amino acid) contents were higher in the STH sheep than in the crossbred sheep (p < 0.05). The odor activity value (OAV) analysis showed that most of the aldehydes in the Au × STH offspring had higher values. The PDK4 gene expression was positively associated with the IMF content and was negatively correlated with the linoleic acid content in the Do × STH sheep (p < 0.05). The TMEM273 gene expression was positively associated with linoleic and arachidonic acid contents and was negatively correlated with oleic and palmitic acid contents in the Do × STH sheep (p < 0.05).

Discussion

The results showed the differences between the crossbred sheep and STH sheep and provided the candidate genes related to meat quality in sheep.

Dietary spirulina platensis a promising growth promotor and immune stimulant in broiler chickens

Algae, as a biological component of the environment, holds promise for the development of novel cuisines. This study aimed to appreciate the dietary Spirulina platensis (SP) impact on growth patterns and as an immune stimulant in broilers. SP-fed chicks at 0.5, 1, and 2 g/kg doses significantly improved hematological indices. Also, gas chromatography of fatty acid profile in broiler breast muscles exhibited greater elevation. Serum total proteins, albumin, and globulin levels significantly increased. ElISA (enzyme-linked immunosorbent assay) revealed elevated immunoglobin M, G, and leptin levels as mirrors for immunological response coordination. Reverse transcription polymerase chain reaction (RT-PCR) exhibited depressed tumour necrosis factor-alpha gene expression (TNF-α) in ilial tissue. Gut's histopathology showed well-developed villi. In conclusion, Spirulina platensis in doses up to 2 g/kg enhances immunity, fatty acid profile, liver function, anti-inflammatory properties, and intestinal absorption of broilers, while doses up to 4 g/kg cause the opposite effect on previous parameters.

Bioefficacy of dietary inclusion of Nannochloropsis oculata on Eimeria spp. challenged chicks: clinical approaches, meat quality, and molecular docking

Although anticoccidial drugs have been used to treat avian coccidiosis for nearly a century, resistance, bird harm, and food residues have caused health concerns. Thus, Nannochloropsis oculata was investigated as a possible coccidiosis treatment for broilers. A total of 150 1-day-old male Cobb broiler chicks were treated as follows: G1-Ng: fed a basal diet; G2-Ps: challenged with Eimeria spp. oocysts and fed basal diet; G3-Clo: challenged and fed basal diet with clopidol; G4-NOa: challenged and fed 0.1% N. oculata in diet, and G5-NOb: challenged and fed 0.2% N. oculata. Compared to G2-Ps, N. oculata in the diet significantly (P < 0.05) decreased dropping scores, lesion scores, and oocyst shedding. Without affecting breast meat colour metrics, N. oculata improved meat quality characters. At 28 days of age, birds received 0.2% N. oculata had significantly (P < 0.05) higher serum levels of MDA, T-SOD, HDL, and LDL cholesterol compared to G2-Ps. Serum AST, ALT, and urea levels were all decreased when N. oculata (0.2%) was used as opposed to G2-Ps. Histopathological alterations and the number of developmental and degenerative stages of Eimeria spp. in the intestinal epithelium were dramatically reduced by 0.2% N. oculata compared to G2-Ps. Molecular docking revealed a higher binding affinity of N. oculata for E. tenella aldolase, EtAMA1, and EtMIC3, which hindered glucose metabolism, host cell adhesion, and invasion of Eimeria. Finally, N. oculata (0.2%) can be used in broiler diets to mitigate the deleterious effects of coccidiosis.

Effect of Spirulina platensis Supplementation on Carcass Characteristics, Fatty Acid Profile, and Meat Quality of Omani Goats

In a 70-day study, 36 Jabbali and Sahrawi bucks, aged 11 months, were utilized to evaluate the effects of different levels of spirulina dietary supplement (SP) on carcass characteristics, fatty acid profile, and meat quality traits in Omani goat breeds. The goats were put into six groups of six bucks, each at random. The diet consisted of a conventional concentrate feed ration (CFR) without spirulina (CON), and the CFR diet supplemented with spirulina at the levels of 2 g/head daily (T1) and 4 g/head daily (T2). In general, Sahrawi bucks showed a highly significant response to SP feeding compared with Jabbali bucks. The treatment groups, especially T1, showed a significant increase in average daily gain and carcass traits (body length, leg length, and the rack weight) compared with the CON group of Sahrawi bucks. The weights of omental and kidney fat were also significantly higher in T1 compared with CON and T2 groups of Sahrawi goats, while they were significantly higher in T2 compared with CON and T1 groups of Jabbali goats. Carcass profile and meat quality, including ultimate ph and meat color lightness (L*) were increased significantly with dietary spirulina in both LD and SM muscles of Sahrawi goats. Most of the Sfa, Mufa, Pufa, Pufa n-6, Pufa n-3, and n-6/n-3 ratios of the LD showed significant differences in diets supplemented with SP compared with CON for Sahrawi bucks, while some of them were significant in Jabbali bucks. The LD muscle of Sahrawi goats fed diets supplemented with SP of the T1 group significantly decreased in the amounts of pentadecanoic and margaric acids compared with the T2 and CON groups. The study concluded that incorporating SP (2 g and 4 g/head daily) into the diet of Omani goats, especially Sahrawi goats, can increase growth performance, as well as improve fatty acid composition and meat quality.

Yolk Fatty Acid Content, Lipid Health Indices, and Oxidative Stability in Eggs of Slow-Growing Sasso Chickens Fed on Flaxseed Supplemented with Plant Polyphenol Extracts

Previous attempts to increase the level of flaxseed in hens' diet for the production of n-3 polyunsaturated fatty acids (n-3 PUFAs)-enriched eggs have been commonly associated with undesirable effects on production efficiency, lipid health indices, and oxidative stability of eggs, requiring adequate research attention. This study investigated the effects of feeding a moderate level of flaxseed (FS) and plant polyphenol extracts (PPEs) on fatty acid content, oxidative stability, and lipid health indices in eggs of slow-growing Sasso T451A laying hens. One hundred and five hens were assigned to five groups (seven replicates of three) and fed on FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia), and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diets. The egg yolk content of eicosapentaenoic acid (EPA, C20:5 n-3) in the DA8, TS8, and CD8 diets and docosahexaenoic acid (DHA, C22:6 n-3) in TS8 and CD8 diets significantly (p < 0.05) increased compared with the FS diet. The FS diet significantly increased the malondialdehyde (MDA) content in egg yolks, whereas the TS8 diet decreased it by 67% (p < 0.05). Little difference was observed in yolk fatty acid content between cooked and raw eggs. Production of n-3 PUFA-enriched eggs with favorable lipid health indices was possible through inclusion of PPEs extracted from local plant species grown in Ethiopia and a moderate dose of flaxseed in the diet of laying hens.

In Vitro Antioxidant Activities of Plant Polyphenol Extracts and Their Combined Effect with Flaxseed on Raw and Cooked Breast Muscle Fatty Acid Content, Lipid Health Indices and Oxidative Stability in Slow-Growing Sasso Chickens

Adding flaxseed was found to decrease oxidative stability in feed and increase the antioxidant needs of chicken. This has also been associated with a decrease in the nutritional value and oxidative stability of meat if sufficient dietary antioxidants are not included. Furthermore, dietary flaxseed has been explored in fast-growing chickens as such studies are limited with slow-growing chickens. Thus, this study aimed to evaluate the effects of feeding plant polyphenol extracts as an antioxidant alongside flaxseed on fatty acid content, oxidative stability, and lipid health indices in breast muscle of slow-growing Sasso T451A dual-purpose chicken. A total of 126 chickens assigned to six groups (seven replicates of three) were fed on NC (control and no antioxidants), FS (75 g flaxseed and no antioxidants), VE8 (75 g flaxseed and 800 mg vitamin E), TS8 (75 g flaxseed and 800 mg Thymus schimperi), DA8 (75 g flaxseed and 800 mg Dodonaea angustifolia) and CD8 (75 g flaxseed and 800 mg Curcuma domestica) extract per kg diet. Feeding on CD8 and VE8 in raw and TS8, CD8 and VE8 diets in cooked breast muscle increased (p < 0.05) the C22:6n − 3 (DHA) and C20:5n − 3 (EPA) contents compared to the FS diet. Feeding FS increased (p < 0.05) the malondialdehyde (MDA) content in breast muscle, whereas TS8 in cooked and raw and CD8 and DA8 diets in raw breast muscle decreased it (p < 0.05). No added benefit was observed in feeding VE8 over plant extracts in terms of improving fatty acid composition and lipid health indices and reducing lipid oxidation in breast meat.

Lipidomic specializations of honeybee (Apis mellifera) castes and ethotypes

Honeybees of the same colony combine a near-homogeneous genetic background with a high level of phenotypic plasticity, making them ideal models for functional lipidomics. The only external lipid source of the colony is pollen, a diet rich in polyunsaturated fatty acids (PUFA). It has been suggested that differences in exposure to pollen-derived PUFA could partly explain differences in longevity between honeybee castes. We here investigated whether the membrane composition of honeybees plays roles in the physiological adaptation to tasks of individuals within the colony. Membranes of cell heaters, a group of workers producing heat from their flight muscles to uphold brood nest temperature, were compared to those of different types of non-heaters. We found that the lipidomic profiles of these groups fall into clearly different "lipotypes", characterized by chain length and saturation of phospholipid-bound fatty acyl residues. The nutritional exposure to PUFA during early adult life and pupal development at the lower edge of the natural range of brood nest temperature both suppressed the expression of the cell heater-"lipotype". Because cardiolipins (CL) are the lipid class most clearly differentiating honeybee phenotypes, and CL plays central roles in mitochondrial function, dysfunction and aging, our findings could help to understand these processes in other animals and humans. Taken together, the lipidome analysis of different life stages of workers, fertile queens, and drones lead to the hypothesis that honeybee "lipotypes" might represent adaptations to different energetic profiles and the likelihood of exposure to low temperatures.

Lower Plasmatic Levels of Saturated Fatty Acids and a Characteristic Fatty Acid Composition in the Ovary Could Contribute to the High-Fertility Phenotype in Dummerstorf Superfertile Mice

In recent decades, fertility traits in humans as well as in farm animals have decreased worldwide. As such, it is imperative to know more about the genetics and physiology of increased or high fertility. However, most of the current animal models with reproductive phenotypes describe lower fertility or even infertility (around 99%). The “Dummerstorf high-fertility lines” (FL1 and FL2) are two unique mouse lines selected for higher reproductive performances, more specifically for higher number of pups per litter. We recently described how those superfertile mice managed to increase their reproductive phenotype by doubling the ovulation rate and consequently the litter size compared to the unselected mice of the same founder population. FLs show an unusual estrous cycle length and atypical levels of hormones that link reproduction and metabolism, such as insulin in FL1 and leptin in FL2. Moreover, we described that their higher ovulation rate is mostly due to a higher quality of their oocytes rather than their sheer quantity, as they are characterized by a higher quantity of high-quality oocytes in antral follicles, but the quantity of follicles per ovary is not dissimilar compared to the control. In the present study, we aimed to analyze the lipid composition of the fertility lines from plasma to the gonads, as they can connect the higher reproductive performances with their metabolic atypicalities. As such, we analyzed the fat content of FLs and fatty acid composition in plasma, liver, fat, oocytes of different quality, and granulosa cells. We demonstrated that those mice show higher body weight and increased body fat content, but at the same time, they manage to decrease the lipid content in the ovarian fat compared to the abdominal fat, which could contribute to explaining their ovarian quality. In addition, we illustrate the differences in fatty acid composition in those tissues, especially a lower level of saturated fatty acids in plasma and a different lipid microenvironment of the ovary. Our ongoing and future research may be informative for farm animal biology as well as human reproductive medicine, mostly with cases that present characteristics of lower fertility that could be reversed following the way-of-managing of Dummerstorf high-fertility lines.

Partial replacement of soybean meal with Chlorella vulgaris in broiler diets influences performance and improves breast meat quality and fatty acid composition

Alternative feed ingredients, such as microalgae, may be more sustainable in comparison to conventional feedstuffs that need large amounts of arable land and are often imported. This study evaluates the effects of Chlorella vulgaris various inclusion levels in the diet of broiler chickens on performance, carcass yield, organ measurements, breast meat quality, fatty acids profile, and antioxidant capacity. A total of two hundred forty 5 d old male Ross 308 broilers were randomly allotted to 4 groups (6 replicates of 10 birds each). Each group received either a control diet or a diet where soybean meal was replaced with 10% (CV10%), 15% (CV15%), or 20% C. vulgaris for 40 d. Performance parameters, carcass and meat traits were evaluated. Compared to the control group, birds supplemented with C. vulgaris (15% and 20%) had lower body weight, weight gain, and feed intake (P < 0.0001), whereas no differences were observed between the control and CV10% groups (P > 0.05). Feed conversion ratio did not differ between control and CV groups. Diets containing C. vulgaris significantly increased ileal digesta viscosity, weight and size of several gastrointestinal compartments, as well as breast muscle yield (P < 0.0001). Incorporation of C. vulgaris resulted in yellower breast muscle (P < 0.0001), with significantly increased chlorophyll a (P < 0.05), chlorophyll b, and total carotenoids contents (P < 0.0001). Inclusion of C. vulgaris decreased bacterial count in meat samples in comparison to controls (P < 0.0001). A 20% C. vulgaris inclusion resulted in higher water holding capacity (P < 0.05) and lower cooking loss (P < 0.05). As dietary C. vulgaris increased, concentrations of DHA + EPA (P < 0.05) and n-3 PUFA (P < 0.0001) increased in breast meat, while the n-6/n-3 PUFA ratio decreased (P < 0.0001). Sensory analysis showed that breast meat from the CV10% group had the highest acceptance score. Overall, dietary concentrations of C. vulgaris of up to 20% improve breast meat quality, whereas 10% of C. vulgaris inclusion is recommended.

Are n-3 PUFAs from Microalgae Incorporated into Membrane and Storage Lipids in Pig Muscle Tissues?-A Lipidomic Approach

For the study of molecular mechanisms of to lipid transport and storage in relation to dietary effects, lipidomics has been rarely used in farm animal research. A feeding study with pigs (German Landrace sows) and supplementation of microalgae (Schizochytrium sp.) was conducted. The animals were allocated to the control group (n = 15) and the microalgae group (n = 16). Shotgun lipidomics was applied. This study enabled us to identify and quantify 336 lipid species from 15 different lipid classes in pig skeletal muscle tissues. The distribution of the lipid classes was significantly altered by microalgae supplementation, and ether lipids of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidic acid (PA) were significantly decreased. The total concentration of triacylglycerides (TAGs) was not affected. TAGs with high degree of unsaturation (TAG 56:7, TAG 56:6, TAG 54:6) were increased in the microalgae group, and major abundant species like TAG 52:2 and TAG 52:1 were not affected by the diet. Our results confirmed that dietary DHA and EPA are incorporated into storage and membrane lipids of pig muscles, which further led to systemic changes in the lipidome composition.

Digestibility of Meat Mineral and Proteins from Broilers Fed with Graded Levels of Chlorella vulgaris

The incorporation of sustainable protein sources in animal feeding is a growing trend. So far, no study has investigated in vitro digestion of meat, from broilers fed microalgae, in a human model. This research aimed to evaluate the effect of incorporating Chlorella vulgaris in the broilers diet on human protein digestibility, and mineral bioaccessibility. The study used 240 male Ross 308 broilers randomly allocated to groups fed a control diet or a diet where soybean meal was replaced with 10% (CV10%), 15% (CV15%), or 20% (CV15%) of C. vulgaris for 40 days. The microalga supplementation increased the protein and lowered the fat content in the muscle. Results on the percentages of amino acids highlighted that arginine and threonine proportions increased and lysine and cysteine proportions decreased with microalga inclusion. CV15% and CV20% meat had higher amount of K, Ca, Mg, P, and Fe in raw breasts, improving the nutrient composition of the meat. Cooking caused a decrease in Na and K and an increase in other minerals. CV20% had higher bioaccessibility of K, Ca, Mg, P, and Mg, compared to the control. Replacing soybean meal in broiler feed with higher concentrations of C. vugaris could improve the digestibility of meat protein and minerals.

Insights into molecular pathways and fatty acid membrane composition during the temperature stress response in the murine C2C12 cell model

Daily and seasonal temperature fluctuations are inevitable due to climate change, which highlights the importance of studying the detrimental effects of temperature fluctuations on the health, productivity, and product quality of farm animals. Muscle membrane composition and the molecular signals are vital for muscle cell differentiation and muscle growth, but their response to temperature stress is not well characterized. Temperature changes can lead to modification of membrane components of the cell, which may affect its surroundings and intracellular signaling pathways. Using C2C12 myoblast cells as a model of skeletal muscle development, this study was designed to investigate the effects of high temperature (39 °C and 41 °C) and low temperature (35 °C) on molecular pathways in the cells as well as the cell membrane fatty acid composition. Our results show that several genes were differentially expressed in C2C12 cells cultured under heat or cold stress, and these genes were enriched important KEGG pathways including PI3K-Akt signaling pathway, lysosome and HIF- signaling pathway, Wnt signaling pathway and AMPK signaling pathway. Our analysis further reveals that several membrane transporters and genes involved in lipid metabolism and fatty acid elongation were also differentially expressed in C2C12 cells cultured under high or low temperature. Additionally, temperature stress shifts the fatty acid composition in the cell membranes, including the proportion of saturated, monounsaturated and polyunsaturated fatty acids. This study revealed an interference between fatty acid composition in the membranes and changing molecular pathways including lipid metabolism and fatty acids elongation mediated under thermal stress. These findings will reinforce a better understanding of the adaptive mechanisms in skeletal muscle under temperature stress.

Impact of spawning season on fillet quality of wild pikeperch (Sander lucioperca)

Pikeperch (Sander lucioperca) is a freshwater fish that has become increasingly popular as a food fish. Within this study, the influence of the spawning process on meat quality was investigated. For this purpose, adult pikeperch was examined directly before and after spawning, and compared regarding physical meat parameters and lipid composition. The results indicate that after spawning, the values of the pH, the electrical conductivity and the yellowness value of fillet were significantly higher than those of the animals sampled before spawning. Analysis of the sum of the total lipid content indicates no differences before and after closed season, but differences in the fatty acid profile were present. Despite significant lower MUFA concentrations, the EPA and DHA showed unaffected high contents. Therefore, the fish muscle indicated an equivalent meat quality. Nevertheless, the significant changes of some physical meat quality parameters after spawning season could have a particular impact on the shelf life and storage of the pikeperch fillet, highlighting the need for further research.

Dietary Supplementation with Microalgae (Schizochytrium sp.) Improves the Antioxidant Status, Fatty Acids Profiles and Volatile Compounds of Beef

The purpose of this study was to evaluate the effects of dietary supplementation with microalgae (Schizochytrium sp.) containing docosahexaenoic acid (DHA) on the antioxidant enzyme activity, physicochemical quality, fatty acid composition and volatile compounds of beef meat. Eighteen male Qaidamford cattle were randomly allocated into three treatments (n = 6): no micro-algae supplementation (Control group, C), 100 g microalgae supplementation per bull per day (FD1), and 200 g microalgae supplementation per bull per day (FD2), and fed for 49 days before slaughter. The results showed that, compared with the C group, the addition of DHA-rich microalgae to the diet could significantly increase the total antioxidant capacity (T-AOC) in meat. In the FD2 group, it was found that the concentration of glutathione peroxidase (GSH-Px) was significantly higher than that of the control group (p < 0.05). DHA-rich microalgae supplementation increased polyunsaturated fatty acid (PUFA), eicosapentaenoic acid (EPA; C20:5 n-6), DHA, EPA + DHA, and n-3 PUFA and reduced n-6:n-3 fatty acid ratio. Twenty-four volatile compounds identified in beef were mainly aldehydes, alcohols and ketones from the fingerprints. The contents of short-chain fatty aldehydes, 1-octen-3-ol and 2-pentylfuran, were higher in the FD2 group than in the other two groups. The microalgae diet improved the sensory attribute score of beef. The results demonstrated that dietary supplementation of DHA-rich microalgae improved the antioxidant status, increased the deposition of DHA and enhanced the characteristic flavor of beef.

Effects of endocannabinoids on feed intake, stress response and whole-body energy metabolism in dairy cows

Endocannabinoids, particularly anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are instrumental in regulating energy homeostasis and stress response. However, little is known about the endocannabinoid system (ECS) in ruminants, although EC could improve dairy health and productivity, at least by increasing feed intake. In this study, we report if intraperitoneal (i.p.) AEA and 2-AG administration affects feed intake, whole-body macronutrient metabolism, isolation and restraint stress, and whether diet composition modulates circulating endocannabinoid concentrations in cows. Twenty Simmental cows in late lactation were fed a grass silage and a corn silage based diet. On each diet, cows received daily i.p. injections with either AEA (5 µg/kg; n = 7), 2-AG (2.5 µg/kg; n = 6) or saline (n = 7) for 8 days. Endocannabinoid administration for 5 days under free-ranging (non-stressed) conditions had no effect on feed intake or energy balance, but attenuated the stress-induced suppression of feed intake when housing changed to individual tie-stalls without social or tactile interaction. Endocannabinoids increased whole-body carbohydrate oxidation, reduced fat oxidation, and affected plasma non-esterified fatty acid concentrations and fatty acid contents of total lipids. There was no effect of endocannabinoids on plasma triglyceride concentrations or hepatic lipogenesis. Plasma AEA concentrations were not affected by diet, however, plasma 2-AG concentrations tended to be lower on the corn silage based diet. In conclusion, endocannabinoids attenuate stress-induced hypophagia, increase short-term feed intake and whole-body carbohydrate oxidation and decrease whole-body fat oxidation in cows.

Using Microalgae as a Sustainable Feed Resource to Enhance Quality and Nutritional Value of Pork and Poultry Meat

Cereal grains and soybean meal are the main feedstuffs used in swine and poultry feeding, two of the most consumed meats and of key relevance to food security worldwide. Such crops are grown mostly in North and South America and transported over large distances creating sustainability concerns and, furthermore, are in direct competition with human nutrition. Alternatives to these ingredients are, thus, a pressing need to ensure the sustainability of swine and poultry production. Microalgae seem to be a viable alternative due to their interesting nutritional composition. The use of different microalgae in monogastric feeding has been addressed by different researchers over the last decade, particularly their use as a supplement, whilst their use as a feed ingredient has been comparatively less studied. In addition, the high production costs of microalgae are a barrier and prevent higher dietary inclusion. Studies on the effect of microalgae on meat quality refer mostly to fatty acid composition, using these either as a functional ingredient or as a feedstuff. Within such a context and in line with such a rationale, in this review we address the current research on the topic of the use of microalgae in poultry and swine nutrition, particularly aspects concerning pork and poultry meat quality and nutritional traits.

Microalgal-based feed: promising alternative feedstocks for livestock and poultry production

There is an immediate need to identify alternative sources of high-nutrient feedstocks for domestic livestock production and poultry, not only to support growing food demands but also to produce microalgae-source functional foods with multiple health benefits. Various species of microalgae and cyanobacteria are used to supplement existing feedstocks. In this review, microalgae have been defined as a potential feedstock for domestic animals due to their abundance of proteins, carbohydrates, lipids, minerals, vitamins, and other high-value products. Additionally, the positive physiological effects on products of animals fed with microalgal biomass have been compiled and recommendations are listed to enhance the assimilation of biomolecules in ruminant and nonruminant animals, which possess differing digestive systems. Furthermore, the role of microalgae as prebiotics is also discussed. With regards to large scale cultivation of microalgae for use as feed, many economic trade-offs must be considered such as the selection of strains with desired nutritional properties, cultivation systems, and steps for downstream processing. These factors are highlighted with further investigations needed to reduce the overall costs of cultivation. Finally, this review outlines the pros and cons of utilizing microalgae as a supplementary feedstock for poultry and cattle, existing cultivation strategies, and the economics of large-scale microalgal production.

Low dietary inclusion of nutraceuticals from microalgae improves feed efficiency and modifies intermediary metabolisms in gilthead sea bream (Sparus aurata)

The aim of this work was to evaluate two functional feeds for the gilthead seabream, Sparus aurata, containing low inclusion of two microalgae-based products (LB-GREENboost, LB_Gb; and LB-GUThealth, LB_Gh). Fish (12–13 g) were fed for 13 weeks a control diet or one of the four diets supplemented with both products at 0.5% or 1%. LB_Gb and LB_Gh did not affect specific growth rate or survival, but increased feed efficiency by decreasing feed intake and enlarging the intestines. LB_Gb increased hepatosomatic index and reduced cortisol levels in plasma, while both products lowered plasma lactate. Extensive metabolite and metabolic enzyme profiling revealed that microalgae supplementations, especially 1% LB_Gh: (i) decrease plasma lactate and increase hepatic glycogen, (ii) reduce hepatic gluconeogenesis, (iii) enhance hepatic lipogenic activity and lipid secretion, (iv) led fish to double triglyceride content in muscle and to stimulate its lipid oxidative capacity, and (v) increase the content of monounsaturated fatty acids and the omega-3 alpha-linolenic acid in muscle. This study demonstrates that both microalgae-based products are suited to improve feed efficiency and orchestrate significant changes in the intermediary metabolism in gilthead seabream juveniles.

Effects of Supplementation of Microalgae (Aurantiochytrium sp.) to Laying Hen Diets on Fatty Acid Content, Health Lipid Indices, Oxidative Stability, and Quality Attributes of Meat

The present study is conducted to investigate the effects of dietary docosahexaenoic acid (DHA)-rich microalgae (MA, Aurantiochytrium sp.) on health lipid indices, stability, and quality properties of meat from laying hens. A total of 450 healthy 50-wk-old Hy-Line Brown layers were randomly allotted to 5 groups (6 replicates of 15 birds each), which received diets supplemented with 0, 0.5, 1.0, 1.5, and 2.0% MA for 15 weeks. Fatty acid contents and quality properties of breast and thigh muscles from two randomly selected birds per replicate (n = 12) were measured. The oxidative stability of fresh, refrigerated, frozen, and cooked meat was also determined. Results indicated that supplemental MA produced dose-dependent enrichments of long-chain n-3 polyunsaturated fatty acids (n-3 LC-PUFA), predominantly DHA, in breast and thigh muscles, with more health-promoting n-6/n-3 ratios (1.87-5.27) and favorable lipid health indices (p < 0.05). MA supplementation did not affect tenderness (shear force) and color (L*, a*, and b* values) of hen meat nor muscle endogenous antioxidant enzymes and fresh meat oxidation (p > 0.05). However, the n-3 LC-PUFA deposition slightly increased lipid oxidation in cooked and stored (4 °C) meat (p < 0.05). In conclusion, MA supplementation improves the nutritional quality of hen meat in terms of lipid profile without compromising meat quality attributes. Appropriate antioxidants are required to mitigate oxidation when such DHA-enriched meat is subjected to cooking and storage.

Consequences of Maternal Essential Fatty Acid and Conjugated Linoleic Acid Supplementation on the Development of Calf Muscle and Adipose Tissue

Common silage and concentrate-based diets in dairy and beef production may deliver insufficient amounts of essential fatty acids (EFA), thereby also reducing conjugated linoleic acids (CLA) in body tissues and milk. An impaired maternal EFA and CLA supply can have an important impact on calf postnatal development. The current study investigates how maternal supplementation with EFA and CLA affects muscle and adipose tissue development in neonatal calves. Holstein cows (n = 40) were abomasaly supplemented with coconut oil (control), CLA or EFA, or both combined during the transition period. Calves were fed their dam's colostrum until slaughter at day 5 of life. Fatty acid composition and tissue morphology were analyzed. In muscle and adipose tissues, EFA, CLA, and metabolites were elevated, indicating the effective transfer of maternally-supplemented FA to the offspring. Muscle fiber types, fiber nuclei, myosin heavy chain isoform distribution, capillarization, and fat cell size of intramuscular and other adipose tissues did not differ among groups. The results confirm that maternal nutrition during the transition period can alter the FA composition of the calf tissues. This could influence the offspring's development and health in the long-term, even though only minor effects were observed in the neonatal calves' tissue morphology.

Fatty Acid Composition in Blubber, Liver, and Muscle of Marine Mammals in the Southern Baltic Sea

Simple Summary

Marine mammals play an important role in marine ecosystems. However, as they are less accessible for research, relatively little is known about their physiology compared to terrestrial mammals. The stranding scheme of the Deutsches Meeresmuseum (Stralsund, Germany) continuously collects strandings and by-catches of marine mammals in the Baltic Sea in Mecklenburg-Western Pomerania. In this project, the fatty acid composition of the liver, skeletal muscles, and blubber of harbour porpoises and grey seals from the southern Baltic Sea was investigated for the first time. In the liver and blubber tissue, the values and concentrations measured for both species are consistent with studies on other marine mammals. In a direct comparison of the focus species, the skeletal muscles of harbour porpoises exhibit higher concentrations of fatty acids than those of grey seals. In the future, these studies will be extended to the entire Baltic Sea, as we suspect that fatty acid composition can be used to determine the nutritional status of the animals and thus will allow for an objective assessment of the body condition.

Abstract

To date, only limited results on the fatty composition in different tissues of the top predators in the Baltic Sea are available. In the current study, tissue samples of blubber, skeletal muscle, and liver from 8 harbour porpoise (Phocoena phocoena) and 17 grey seals (Halichoerus grypus) in the Baltic Sea off Mecklenburg-Western Pomerania were included in the investigation. While the total fatty acid content in liver and blubber tissue revealed no differences between both species, the total fatty acid content of muscle tissue was significantly differentand showed higher concentrations in harbour porpoise muscle compared with grey seals. The most abundant fatty acids in the blubber of grey seals and harbour porpoises (18:1cis-9, 16:1cis-9, 16:0 and 22:6n-3) were present in similar quantities and ratios to each other as known from other marine top predators. If future studies can show that differences in tissue fatty acid content are caused by variation in the nutritional status, and this may lead to the development of a more objective assessment of body condition in seals and porpoises recovered via stranding schemes.

Effects of abomasal infusion of essential fatty acids together with conjugated linoleic acid in late and early lactation on performance, milk and body composition, and plasma metabolites in dairy cows

Rations including high amounts of corn silage are currently very common in dairy production. Diets with corn silage as forage source result in a low supply of essential fatty acids, such as α-linolenic acid, and may lead to low conjugated linoleic acid (CLA) production. The present study investigated the effects of abomasal infusion of essential fatty acids, especially α-linolenic acid, and CLA in dairy cows fed a corn silage-based diet on performance, milk composition, including fatty acid (FA) pattern, and lipid metabolism from late to early lactation. Rumen-cannulated Holstein cows (n = 40) were studied from wk 9 antepartum to wk 9 postpartum and dried off 6 wk before calving. The cows were assigned to 1 of 4 treatment groups. Cows were abomasally supplemented with coconut oil (CTRL, 76 g/d), linseed and safflower oil (EFA, 78 and 4 g/d; linseed/safflower oil ratio = 19.5:1; n-6/n-3 FA ratio = 1:3), Lutalin (CLA, 38 g/d; BASF SE, Ludwigshafen, Germany; isomers cis-9,trans-11 and trans-10,cis-12 each 10 g/d) or EFA+CLA. Milk composition was analyzed weekly, and blood samples were taken several times before and after parturition to determine plasma concentrations of metabolites related to lipid metabolism. Liver samples were obtained by biopsy on d 63 and 21 antepartum and on d 1, 28, and 63 postpartum to measure triglyceride concentration. Body composition was determined after slaughter. Supplementation of CLA reduced milk fat concentration, increased body fat mass, and improved energy balance (EB) in late and early lactation, but EB was lowest during late lactation in the EFA group. Cows with CLA treatment alone showed an elevated milk citrate concentration in early lactation, whereas EFA+CLA did not reveal higher milk citrate but did have increased acetone. Milk protein was increased in late lactation but was decreased in wk 1 postpartum in CLA and EFA+CLA. Milk urea was reduced by CLA treatment during the whole period. After calving, the increase of nonesterified fatty acids in plasma was less in CLA groups; liver triglycerides were raised lowest at d 28 in CLA groups. Our data confirm an improved metabolic status with CLA but not with exclusive EFA supplementation during early lactation. Increased milk citrate concentration in CLA cows points to reduced de novo FA synthesis in the mammary gland, but milk citrate was less affected in EFA+CLA cows, indicating that EFA supplementation may influence changes in mammary gland FA metabolism achieved by CLA.

Effect of Dietary Microalgae on Growth Performance, Profiles of Amino and Fatty Acids, Antioxidant Status, and Meat Quality of Broiler Chickens

Simple Summary

The use of feed additives with no side effectsfor enhancing growth performance and improving meat quality in broilers chickens is an essential research topic. In these regards, this study aimed to evaluate the impact of three species of microalgae namely Chlorella vulgaris (CV), Spirulina platensis (SP) and Amphora coffeaformis (AC) on growth performance, profiles of fatty and amino acids, antioxidant status and meat quality of breast muscles. The results demonstrated that the inclusion of studied microalgae notably AC has a positive effect on performance, antioxidant status and meat quality of breast muscle in broiler chickens.

Abstract

The study used 96 broiler chickens to evaluate the impact of three species of microalgae on performance, profiles of fatty and amino acids, antioxidants, and meat quality of breast muscles. Birds were divided into four groups (24 birds/each) with 4 replicates (6 birds each). Birds in the first group were fed basal diet and served as a control (C). Birds of 2–4 groups were fed basal diet mixed with same dose (1 g/kg diet) of Chlorella vulgaris (CV), Spirulina platensis (SP), and Amphora coffeaformis (AC). At the age of 36 days, performance parameters were reported, and breast muscle samples were collected and stored frozen at −80 °C. AC shared CV in the superiority of increasing final body weight and body weight gain compared to SP and control. AC shared SP in the superiority of increasing the level of essential fatty and amino acids and decreasing the microbial growth in breast muscle compared to CV and control. All studied microalgae reduced malondialdehyde (MDA) and protein carbonyl (PC) levels, cooking loss, and aerobic plate count (APC) and increased the superoxide dismutase (SOD) activities in breast muscle compared to control. The current study indicated that studied microalgae, notably AC, can be used to enhance performance and meat quality in broilers chickens.

Resistance and tolerance to mixed nematode infections in relation to performance level in laying hens

Modern chickens have been genetically developed to perform high under optimal conditions. We hypothesized that high-performance is associated with a higher sensitivity to environmental challenges in laying hens. By using nematode infections as an environmental stressor, we assessed performance-level associated host responses in a high (i.e. Lohmann Brown Plus, LB) and in a lower performing, a so-called dual-purpose chicken genotype (i.e. Lohmann Dual, LD). The hens were infected with 1000 eggs of Ascaridia galli and Heterakis gallinarum at 24 weeks of age. Hen performance parameters, humoral immune responses in plasma and egg yolks and worm burdens were assessed at several occasions over a period of 18 weeks post infection (wpi). While infections had no significant effect on feed intake (P = 0.130) and body weight in both genotypes (P = 0.392), feed conversion efficiency was negatively affected by infections (P = 0.017). Infections reduced both laying rate and egg weight and thereby per capita egg mass in both genotypes (P < 0.05). While laying rate in infected LB hens decreased significantly (P < 0.05) in the early infection period (i.e. by 3 wpi), the decrease in LD hens appeared much later (i.e. by 14 wpi). Worm burdens resulting from the experimental infection were not different between the genotypes for both worm species (P > 0.05), whereas LB hens were more susceptible (P < 0.05) to re-infections than LD hens. Changes in humoral immune responses (i.e. ascarid-specific IgY antibodies in plasma and egg yolks) of the two genotypes over time reflected closely the corresponding changes in larval counts of the hens, descending from both experimental and subsequent natural infections in both genotypes. Infections caused a shift in egg size classes, leading to smaller frequency of larger eggs in both genotypes. Infections reduced egg weight (P = 0.018) and led to a reduced fat content in the egg yolks (P = 0.045). The proportion of poly-unsaturated fatty acids (PUFA), especially n-6-PUFA, was also lower in egg yolks of the infected hens (P = 0.032). We conclude that tolerance to nematode infections in laying hens is dependent on host-performance level. The impairment in host tolerance was both genotype and time dependent, likely due to differences in genetic programming for production peak and persistency of the two genotypes. The two genotypes exhibited similar levels of resistance after a fully controlled experimental infection, but the high performing hens were more susceptible to subsequent natural infections. Infections negatively affected economically important egg-quality traits, including egg weight, fat content and fatty acid profiles in egg yolks.