Positive impacts of Nannochloropsis oculata supplementation on gene expression of immune and antioxidant markers and metabolic profile of Barki sheep in the transition period and lipogenic effects on progeny

Nannochloropsis species should be given priority when it comes to microalgae that should be added to feed since they are suitable for intense culture and have a high concentration of PUFAs (especially EPA), antioxidants, and certain vitamins. This study investigated the possible immune and antioxidant impacts of Nannochloropsis supplementation on Barki ewes during transition period and their newly born lambs. Three weeks prior to the expected time of lambing, the researched ewes were divided into two equal groups of thirty ewes each. The second group, on the other hand, was fed the same base diet as the first group plus 10 g of commercially available Nannochloropsis powder per kg of concentrate, given daily to each ewe's concentrate. Findings revealed that supplementation of ewes with Nannochloropsis significantly up-regulated the expression pattern of immune (NFKB, RANTES, HMGB1, TNF-α, IRF4, TLR7, CLA-DRB3.2, IL1B, IL6, CXCL8, S-LZ, and Cathelicidin), and antioxidant (SOD1, CAT, GPX1, GST, ATOX1, Nrf2 and AhpC/TSA) markers in ewes post-lambing and their newly born lambs. Additionally, mRNA levels of lipogenic (ACACA, FASN SCD, LPL, and BTN1A) markers were significantly up-regulated in lambs from supplemented ewes than control ones. There was a significant increase in the WBCs, Hb, RBc count, serum level of glucose, total protein, triacylglycerol and total cholesterol, GPx, catalase, IL1α and IL6 with significantly decreased serum level of TNF-α and MDA in supplemented ewes after lambing as compared with control ones. There was also a significant increase in WBCs, Hb, RBc count, birth weight and body temperature with significantly decreased in the serum levels of TNF-α and stillbirth of newly born lambs from supplemented ewes as compared to other lambs from control ones.

Partial substitution of soybean meal with microalgae meal (Arthrospira spp. - Spirulina) in grower and finisher diets for broiler chickens: implications on performance parameters, footpad dermatitis occurrence, breast meat quality traits, amino acid digestibility and plasma metabolomics profile

This trial was conducted to evaluate the effects of replacing soybean meal with microalgae meal (MM; Arthrospira spp.) during grower and finisher phases on productive performance, footpad dermatitis (FPD) occurrence, breast meat quality, amino acid digestibility and plasma metabolomics profile of broiler chickens. One thousand day-old Ross 308 male chicks were divided into 5 experimental groups (8 replicates, 25 birds/each): CON, fed a commercial soybean-based diet throughout the trial (0-41 d); F3 and F6, fed the CON diet up to 28 d of age and then a finisher diet (29-41 d) with either 30 or 60 g MM/kg, respectively; and GF3 and GF6, receiving CON diet until 14 d and then diets containing 30 or 60 g MM/kg from 15 to 41 d, respectively. All diets were iso-energetic and with a similar amino acid profile. Growth performances were recorded on a pen basis at the end of each feeding phase and apparent ileal amino acid digestibility was determined at 41 d. Footpad dermatitis occurrence was assessed on all processed birds, while breast and plasma samples were collected for meat quality and metabolomics analysis (proton nuclear magnetic resonance - 1H-NMR). At 41 d, CON group showed higher body weight than F6 and GF6 ones (2,541 vs. 2,412 vs. 2,384 g, respectively; P < 0.05). Overall, GF6 group exhibited the highest feed conversion ratio, while F3 did not present significant differences compared to CON (1.785 vs. 1.810 vs. 1.934 g feed/g gain, respectively for CON, F3 and GF6; P < 0.01). The occurrence and the risk of developing FPD were similar among groups. MM administration increased breast meat yellowness and reduced amino acid digestibility (P < 0.001). The 1H-NMR analysis revealed variations in the levels of some circulating metabolites, including histidine, arginine and creatine, which play important metabolic roles. Overall, these findings can contribute to expand the knowledge about the use of Arthrospira spp. as protein source in broiler diets.

Dietary supplementation with Chlorella vulgaris in broiler chickens submitted to heat-stress: effects on growth performance and meat quality

Heat stress can greatly challenge growth and meat quality of broiler chickens where research is looking for sustainable ingredients, such as microalgae, that could also alleviate its negative impacts. Thus, in the present study, 576 1-D-old chicks (Ross 308) were housed until commercial slaughtering (42 D) in 36 pens in 2 rooms of a poultry house, according to a full factorial design encompassing 2 room temperatures (standard vs. high), 2 sexes (females vs. males), and 3 dietary treatments, that is, diet C0 (control diet), diet C3, and diet C6 containing 0, 3, and 6%, respectively, of C. vulgaris meal replacing the same quantities of soybean meal. The highest inclusion level of C. vulgaris decreased feed intake (P < 0.001) and body weight (P < 0.0001) compared to the control diet; it increased yellow and red indexes (P < 0.0001) of the breast muscle, besides the proportion of n3 polyunsaturated fatty acids (PUFA) (P = 0.028). Heat stress decreased feed intake (P = 0.001), breast (P = 0.001) and p. major yields (P = 0.036), and increased meat pH (P= 0.008) and cooking losses (P < 0.001), umami (P = 0.021) and brothy flavor (P < 0.001), and the proportion of n3 PUFA rates (P = 0.027), while reducing the contents of several amino acids in the breast meat (P ≤ 0.05). Compared to females, males displayed higher feed intake and growth, and more favorable feed conversion (P < 0.001). Carcass and p. major yields were greater in females (P < 0.001) which also showed a higher occurrence of spaghetti meat compared to males (P < 0.001). In conclusion, C. vulgaris can be used to replace until 3% of soybean meal in diets for broiler chickens without negative implications, while positively affecting breast meat color according to consumers' preferences. However, the microalgae inclusion did not mitigate the negative effects of a chronic heat stress on growth performance nor reduced the occurrence of any myopathies.

Effects of high dietary inclusion of Arthrospira platensis, either extruded or supplemented with a super-dosing multi-enzyme mixture, on broiler growth performance and major meat quality parameters

BACKGROUND

This investigation assessed the effects of high dietary inclusion of Spirulina (Arthrospira platensis) on broiler chicken growth performance, meat quality and nutritional attributes. For this, 120 male broiler chicks were housed in 40 battery brooders (three birds per brooder). Initially, for 14 days, a standard corn and soybean meal diet was administered. Subsequently, from days 14 to 35, chicks were assigned to one of the four dietary treatments (n = 10 per treatment): (1) control diet (CTR); (2) diet with 15% Spirulina (SP); (3) diet with 15% extruded Spirulina (SPE); and (4) diet with 15% Spirulina plus a super-dosing enzymes supplement (0.20% pancreatin extract and 0.01% lysozyme) (SPM).

RESULTS

Throughout the experimental period, both SP and SPM diets resulted in decreased final body weight and body weight gain compared to control (p < 0.001), with the SPE diet showing comparable results to CTR. The SPE diet prompted an increase in average daily feed intake (p = 0.026). However, all microalga treatments increased the feed conversion ratio compared to CTR. Dietary inclusion of Spirulina notably increased intestinal content viscosity (p < 0.010), which was mitigated by the SPM diet. Spirulina supplementation led to lower pH levels in breast meat 24 h post-mortem and heightened the b* colour value in both breast and thigh meats (p < 0.010). Furthermore, Spirulina contributed to an increased accumulation of total carotenoids, n-3 polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA), while diminishing n-6 PUFA, thus altering the n-6/n-3 and PUFA/SFA ratios favourably (p < 0.001). However, it also reduced zinc concentration in breast meat (p < 0.001).

CONCLUSIONS

The findings indicate that high Spirulina levels in broiler diets impair growth due to increased intestinal viscosity, and that extrusion pre-treatment mitigates this effect. Despite reducing digesta viscosity, a super-dosing enzyme mix did not improve growth. Data also indicates that Spirulina enriches meat with antioxidants and n-3 PUFA but reduces α-tocopherol and increases saturated fats. Reduced zinc content in meat suggests the need for Spirulina biofortification to maintain its nutritional value.

Effects of the algae derivatives on performance, intestinal histomorphology, ileal microflora, and egg yolk biochemistry of laying Japanese quail

We examined the effect of the Persian Gulf algae derivates, phycocyanin (PC) and fucoidan (FUC), on production performance, egg quality, intestinal histomorphology, ileal microflora, and egg yolk biochemistry of laying Japanese quail. A total of 250 six-wk-old Japanese quails with an average body weight of 215 ± 10 g were allocated to 5 treatments, 5 replicates and 10 birds in each replicate in a completely randomized design. The treatment groups received PC (from Spirulina platensis) and FUC (from brown seaweed) in their drinking water while control groups did not. Treatment groups received PC and FUC at 20 or 40 mg/L levels (denoted as PC20, PC40, FUC20, and FUC40, respectively). All birds were fed the same diet. All treatments significantly improved the percentage of hen day egg production (HDEP) (P = 0.002), egg mass (P = 0.002), and feed conversion ratio (FCR) (P = 0.022) but no difference was noted in egg weight (EW) and feed intake (FI). Different levels of PC and FUC significantly increased the thickness of eggshells (P = 0.022); however, the weight of the digestive tract (liver, spleen, proventriculus, gizzard, and pancreas) and oviduct was not affected. Algal derivates improved the villus height (P = 0.007) and crypt depth (P = 0.007) of the duodenum, as well as, the villus height (P = 0.005) and crypt depth (P = 0.026) of the jejunum. Both algal derivates positively affected the intestinal microflora (populations of Lactobacillus (P = 0.017), Coliform (P = 0.005), and Clostridium (P = 0.000)) whereas aerobic bacteria were unaffected. Yolk cholesterol P = 0.012) and yolk malondialdehyde P = 0.050) content were significantly reduced in experimental treatments compared to the control group. In conclusion, our results showed that the treatment of laying Japanese quails with algal derivates positively affects quail performance, intestinal morphology, intestinal microflora, and yolk cholesterol and malondialdehyde. Additional studies exploring optimal dosages and mechanisms of action is warranted to fully understand the scope of the algae derivates in poultry production.

Effect of dietary Arthrospira platensis phycocyanin on broiler chicken growth performance, physiological status, fatty and amino acid profiles

Background and Aim

Natural antioxidants are crucial for preserving and enhancing the health, survival, reproduction, and reproductive function of poultry. Phycocyanin (PC) is a natural blue food colorant with various health benefits. The aim of this study was to extract Arthrospira platensis phycocyanin (ApPC) from A. platensis using simple and economical methods and investigate the impact of phytocyanin supplementation on the performance and fatty and amino acid profiles of broiler chicks.

Materials and Methods

PC was extracted from A. platensis by freezing and thawing, and optimization conditions such as pH and temperature were applied during storage periods. A total of 270 1-week-old Ross breed broiler chicks were randomly assigned to the following three treatment groups: basal diet supplemented with 0 mg of PC/kg diet (control), basal diet supplemented with 1 g PC/kg diet (T1), and basal diet supplemented with 2 g PC/kg (T2). In a completely randomized design, three cage replicates (30 birds each) were assigned to each of the three groups. The dietary effects of ApPC on growth performance (body weight gain [BWG], body weight [BW], feed intake, feed conversion ratio, serum constituents, and antioxidant indices) in broiler chickens, free amino acids, and fatty acids in muscles were evaluated.

Results

Total BWG and BW increased without a significant effect on the total feed consumption. Serum levels of total proteins and albumin increased with increasing ApPC supplementation. In addition, globulin levels significantly increased. There was a significant decrease in serum total cholesterol levels among the treatments. The activity of antioxidant enzymes (superoxide dismutase, catalase, glutathione, and total antioxidant capacity) is significantly increased. In contrast, an increase in ApPC caused a significant decrease in malondialdehyde. The content and quantity of fatty acids and amino acids in the meat of broiler chicks supplemented with PC varies.

Conclusion

The addition of PC to broiler chicken diets enhances antioxidant activities, BW, BWG, and meets quality requirements.

Algae as an alternative source of protein in poultry diets for sustainable production and disease resistance: present status and future considerations

Integrating algae into poultry diets offers a promising avenue for enhancing nutrition, boosting sustainability efforts, and potentially stimulating disease resistance. This comprehensive review delves into the essence, diversity, chemical composition, and nutritional merits of algae, spotlighting their emergence as innovative nutrient sources and health supplements for poultry. The growing interest in algae within poultry nutrition stems from their diverse nutritional profile, boasting a rich array of proteins, lipids, amino acids, vitamins, minerals, and antioxidants, thus positioning them as valuable feed constituents. A key highlight of incorporating both macroalgae and microalgae lies in their elevated protein content, with microalgae varieties like Spirulina and Chlorella exhibiting protein levels of up to 50-70%, outperforming traditional sources like soybean meal. This premium protein source not only furnishes vital amino acids crucial for muscular development and overall health in poultry but also serves as an exceptional reservoir of omega-3 fatty acids, notably eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), presenting multiple health benefits for both poultry and consumers alike. Moreover, algae boast antioxidant properties attributed to bioactive compounds like phycocyanin and astaxanthin, mitigating oxidative stress and boosting the bird's immune response, thereby fostering robust health and disease resilience. Incorporating macroalgae and microalgae into poultry diets yields positive impacts on performance metrics. Research evidence underscores the enhancement of growth rates, feed conversion ratios, carcass quality, and meat attributes in broilers, while in layers, supplementation promotes increased egg production, superior egg quality, and increased concentrations of beneficial nutrients such as omega-3 fatty acids. Furthermore, algae hold promise for mitigating the environmental footprint of poultry production, though significant outcomes from trials remain sporadic, necessitating further research to elucidate optimal dosages and blends for different algae species in poultry diets. Standardizing the composition of algae utilized in research is imperative, paving the way for potential applications in poultry nutrition as growth stimulants and substitutes for antibiotics. Nonetheless, a deeper understanding of dosage, combination, and mechanism of action through rigorous scientific investigation is key to unlocking algae's full potential within poultry nutrition.

Effects of varying dietary microalgae levels on performance, egg quality, fertility, and blood biochemical parameters of laying Japanese quails (Coturnix coturnix Japonica)

This experiment was carried out to investigate the nutritional value of Spirulina and Dunaliella (SD) combination levels (0, 0.5, 1.0, 1.5, and 2.0 g/kg) that affected the laying Japanese quail's efficiency, egg quality, fertility, and blood biological indicators. A total of 150 adult Japanese quails, aged 8 wk, were divided into 5 treatments at random, each consisting of 30 quails. There were 5 duplicates for every treatment, with 2 male and 4 female quails in each. Comparing the addition of various concentrations of a mixture of SD to the control treatment, the results showed no substantial rise in egg production, egg weight, or egg mass. When compared to the control group, final body weight (FBW) was improved with SD supplementation. The quails in control consumed more feed intake (FI) (p < 0.05), and they were different from the groups who got SD therapy in that they had a regular feed conversion ratio (FCR). The percentages of hatchability and fertility increased when SD was added to quail meals at up to 1.00 g/kg. When compared to the control quail, the quail supplemented with SD levels showed a non-significant rise in albumin%, yolk%, Haugh unit, and unit surface shell weight (USSW), as well as an increase in eggshell percentage and a drop in egg shape index (p < 0.05). Renal and hepatic enzyme functioning improved when SD was added to the diets. Additionally, lipid profile indicators were reduced by SD supplementation (except low-density lipoprotein-LDL). Moreover, compared to the control, incorporating SD led to a nonsignificant rise in immunoglobulin concentrations (IgG and IgM). In conclusion, adding SD to the diet can improve body weight, lipid profile, immunological response, and liver and kidney functions in Japanese quail.

Effect of a microencapsulated phyto/phycogenic blend supplementation on growth performance, processing parameters, meat quality, and sensory profile in male broilers

Powered by consumer taste, value, and preferences, natural products including phytogenics and algae are increasingly and separately used in the food systems where they have been reported to improve growth performance in poultry and livestock. The present study aimed to determine the effects of a new feed additive, microencapsulated NUQO© NEX, which contains a combination of phytogenic and phycogenic, on broiler growth performance, blood chemistry, bone health, meat quality and sensory profile. Male Cobb500 chicks (n = 1,197) were fed a 3-phase feeding intervals; 1-14d starter, 15-28d grower, and 29-40d finisher. The dietary treatments included a corn-soy basal Control (CON), basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 28d then 75 g/ton from d 28 to 40 (NEX75), and basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 40d (NEX100). The NEX100 supplemented birds had 62 g more BWG increase and 2.1-point improvement in FCR compared with CON in the finisher and overall growth phase (p < 0.05), respectively. Day 40 processing body weights and carcass weights were heavier for the NEX100 supplemented birds (p < 0.05). The incidences of muscle myopathies were also higher in NEX treatments, which could be associated with the heavier weights, but the differences were not detected to be significant. The NEX75 breast filets had more yellowness than other dietary treatments (p = 0.003) and the NEX 100 treatment reduced the levels of breast filet TBARS at 7 days-post harvest (p = 0.053). Finally, both NEX treatments reduced the incidence of severe bone (tibia and femur) lesions. In conclusion, the supplementation of the phytogenic NUQO© NEX improved finisher performance parameters, whole phase FCR, processing carcass weights, and breast filet yellowness, at varying inclusion levels.

Impact of high Spirulina diet, extruded or supplemented with enzymes, on blood cells, systemic metabolites, and hepatic lipid and mineral profiles of broiler chickens

The impact of 15% dietary inclusion of Spirulina (Arthrospira platensis) in broiler chickens was explored, focusing on blood cellular components, systemic metabolites and hepatic lipid and mineral composition. From days 14 to 35 of age, 120 broiler chickens were divided and allocated into four dietary treatments: a standard corn and soybean meal-based diet (control), a 15% Spirulina diet, a 15% extruded Spirulina diet, and a 15% Spirulina diet super-dosed with an enzyme blend (0.20% porcine pancreatin plus 0.01% lysozyme). The haematological analysis revealed no significant deviations (p > 0.05) in blood cell counts across treatments, suggesting that high Spirulina inclusion maintains haematological balance. The systemic metabolic assessment indicated an enhanced antioxidant capacity in birds on Spirulina diets (p < 0.001), pointing toward a potential reduction in oxidative stress. However, the study noted a detrimental impact on growth performance metrics, such as final body weight and feed conversion ratio (both p < 0.001), in the Spirulina-fed treatments, with the super-dosed enzyme blend supplementation failing to alleviate these effects but with extrusion mitigating them. Regarding hepatic composition, birds on extruded Spirulina and enzyme-supplemented diets showed a notable increase in n-3 fatty acids (EPA, DPA, DHA) (p < 0.001), leading to an improved n-6/n-3 PUFA ratio (p < 0.001). Despite this positive shift, a reduction in total hepatic lipids (p = 0.003) was observed without a significant change in cholesterol levels. Our findings underscore the need for further exploration into the optimal inclusion levels, processing methods and potential enzymatic enhancements of Spirulina in broiler diets. Ultimately, this research aims to strike a balance between promoting health benefits and maintaining optimal growth performance in poultry nutrition.

Microalgae as an Alternative Mineral Source in Poultry Nutrition

This review explores the potential of microalgae as a sustainable and nutritionally rich alternative for mineral supplementation in poultry diets, addressing both the opportunities and challenges in this emerging field. Poultry nutrition, pivotal to the health and productivity of birds, traditionally relies on inorganic and organic mineral sources which, while effective, raise environmental and economic concerns. Microalgae offer a promising solution with their high contents of essential minerals, proteins, vitamins, and bioactive compounds. This review delves into the nutritional profiles of various microalgae, highlighting their rich contents of minerals which are crucial for physiological processes in poultry. It examines the bioavailability of these minerals and their impact on poultry health and productivity. Furthermore, it evaluates the environmental sustainability of microalgae cultivation and acknowledges the challenges in using microalgae in poultry diets, particularly in terms of the economic viability of large-scale production and the consistency of nutrient composition. It discusses the importance of rigorous safety assessments and regulatory compliance, given the potential risks of toxins and heavy metals. Overall, this analysis aims to provide a clear understanding of the role microalgae could play in poultry nutrition and address sustainability challenges in animal agriculture while also considering future perspectives and advancements needed in this field.

Alternative and Sustainable Protein Sources in Pig Diet: A Review

The search for alternative protein sources to soybean meal (SBM) in animal feeding is a strategic objective to reduce production costs and contribute to sustainable animal production. Spirulina, due to the high protein content, has emerged as a potential cost-effective, sustainable, viable, and high-nutritional-value food resource for many animal species. Insect larvae (Tenebrio molitor and Hermetia illucens) are also considered potential alternatives to SBM, given their high edible percentage of almost 100%, as well as a protein value higher than that of vegetable proteins. Rapeseed meal and grain legumes, such as fava beans, peas, lupins, and chickpea, can also be used as locally producible protein ingredients. This study reviews the nutritional value of these potential alternatives to SBM in pig diets, and their effects on animal performance, digestion, immune system, and the physicochemical and sensorial characteristics of meat, including processed pork products. The limits on their use in pig feeding are also reviewed to indicate gaps to be filled in future research on the supplementation level of these potential alternative protein sources in pig diets.

Growth, carcass criteria, and blood biochemical parameters of growing quails fed Arthrospira platensis as a feed additive

This study investigated the impact of Arthrospira platensis (A. platensis) as a dietary supplement on growth, carcass criteria, liver and kidney function, lipid profile, and immunity of growing Japanese quails. In a 28-day experiment, 240 unsexed 7-day-old quail chicks were used. The quail chicks were divided into 4 treatment sets, each comprising 6 replicates and 10 quail chicks. Group (1) fed the basal diet with no supplements, group (2) fed the basal diet supplemented with 0.25 g A. platensis/kg diet, group (3) fed the basal diet supplemented with 0.50 g A. platensis/kg diet, and group (4) fed the basal diet supplemented with 1.00 g A. platensis/kg diet. The results of this study revealed that the birds that were fed 0.50 g. or 1.00 g A. platensis/kg diet had superior final body weights, body weight gains, feed conversion ratios, and carcass criteria compared to control, furthermore, had significant (P < 0.05) lower levels of liver enzymes and kidney function markers compared to control. Furthermore, birds fed 0.50 g or 1.00 g A. platensis/kg diet had significantly (P < 0.05) reduced cholesterol, triglycerides, and LDL cholesterol levels compared to control. Dietary supplementation of A. platensis at 0.50 and 1.00 g/kg diet significantly (P < 0.05) increased total antioxidant capacity, total immunoglobulin, and lysozyme activity levels. Using A. platensis at 0.5 or 1 g/kg diet levels during the Japanese quails' growth period can improve growth, carcass criteria, liver and kidney function, lipid profile, and immunity.

Microalgae as a Sustainable Source of Antioxidants in Animal Nutrition, Health and Livestock Development

Microalgae are a renewable and sustainable source of bioactive compounds, such as essential amino acids, polyunsaturated fatty acids, and antioxidant compounds, that have been documented to have beneficial effects on nutrition and health. Among these natural products, the demand for natural antioxidants, as an alternative to synthetic antioxidants, has increased. The antioxidant activity of microalgae significantly varies between species and depends on growth conditions. In the last decade, microalgae have been explored in livestock animals as feed additives with the aim of improving both animals' health and performance as well as product quality and the environmental impact of livestock. These findings are highly dependent on the composition of microalgae strain and their amount in the diet. The use of carbohydrate-active enzymes can increase nutrient bioavailability as a consequence of recalcitrant microalgae cell wall degradation, making it a promising strategy for monogastric nutrition for improving livestock productivity. The use of microalgae as an alternative to conventional feedstuffs is becoming increasingly important due to food-feed competition, land degradation, water deprivation, and climate change. However, the cost-effective production and use of microalgae is a major challenge in the near future, and their cultivation technology should be improved by reducing production costs, thus increasing profitability.

Safety Evaluation of a Novel Algal Feed Additive for Poultry Production

Feed additives are critical components for poultry health and the economic viability of antibiotic-free poultry production. The aim of the present study is to evaluate the safety of a novel algal-derived feed additive, a dried biomass powder produced from Chlamydomonas reinhardtii strain crAL082, modified to express an N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28) and a lysozyme-type enzyme (EC 3.2.1.17). A 42-day oral toxicity study showed that the crAL082 dried biomass powder was fully tolerated by broiler chicken based on the lack of detrimental effects found in performance, mortality, hematology, blood clinical chemistry, and histopathologic results compared with those of a nontreated control group, resulting in a "No Observed Adverse Effect Level" of 5000 ppm, the highest dose tested. The study demonstrates the first-ever safety result of a C. reinhardtii microalgae dried biomass powder used as a feed additive in broiler chickens. Furthermore, safety is shown for the two additional enzymes expressed within the C. reinhardtii crAL082 strain and ingested by the birds.

Digestive Constraints of Arthrospira platensis in Poultry and Swine Feeding

Microalgae have emerged as novel sources for monogastric animals' diets since they are rich in many nutrients, including proteins. Arthrospira platensis is particularly rich in proteins (up to 76% of dry matter), lipids, minerals and pigments. However, its rigid peptidoglycan cell wall interferes with the digestibility, bio-accessibility and bioavailability of nutrients for monogastric animals. The aim of the present study was to evaluate the digestibility, bio-accessibility, bioavailability and protein quality of nutrients from A. platensis for poultry and swine feeding, searching all the studies available in PubMed, Web of Science, Scopus and Google Scholar in June 2022 concerning this subject. Overall, digestibility values of A. platensis proteins or amino acids varying from 66.1 to 68.7% for poultry (microalgae at 1% feed) and from 75.4 to 80.6% for swine (10% feed) have been reported. Therefore, the extraction of microalgae components using mechanical or non-mechanical pre-treatments is required to promote cell disruption and improve digestibility and bio-accessibility. Although A. platensis is a promising feedstuff to support future needs, it is important to perform more investigation concerning digestibility, dietary inclusion level and possible treatments to disrupt microalga cell walls and increase bioavailability of nutrients.

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.

Potential ameliorative role of Spirulina platensis in powdered or extract forms against cyclic heat stress in broiler chickens

Global warming has become intensified and widespread, threatening the world with causing acute heatwaves that adversely affect poultry production and producers' profitability. Spirulina platensis is a precious and promising mitigating strategy to combat the detrimental impacts of heat stress due to its high contents of nutrients and bioactive components. The current study was designed to compare the incorporation impact of S. platensis powder or aqueous extract on the growth and physiological responses of heat-stressed broiler chicks. Six hundred 1-day-old Ross 308 male broiler chicks were allocated into five experimental groups with six replicates of 20 chicks each. The control group fed the basal diet without additives, SPP1 and SPP2 groups fed the basal diet with 1 g/kg and 2 g/kg S. platensis powder, respectively, while SPE1 and SPE2 groups received 1 ml/L and 2 ml/L S. platensis aqueous extract in the drinking water, respectively. All birds were exposed to cyclic heat stress (34 ± 2 °C for 12 h) for three successive days a week from day 10 to day 35. In vitro analysis showed that total phenols, flavonoids, and antioxidant activity of S. platensis were remarkably decreased (P < 0.001) in the aqueous extract compared to the powder form. Body weight, weight gain, and feed conversion ratio were improved (P < 0.001) in all treated groups, while carcass yield and dressing percentage were increased only in SPP1 and SPP2. Feed and water intake and blood biochemical parameters were not affected. Both forms of S. platensis enhanced the lipid profile, redox status, and humoral immune response of heat-stressed chicks superior to the powder form. Conclusively, the powder form of S. platensis was more effective in enhancing the productivity of broilers and alleviating the negative impacts of heat stress than the aqueous extract form.

Modulating the Growth, Antioxidant Activity, and Immunoexpression of Proinflammatory Cytokines and Apoptotic Proteins in Broiler Chickens by Adding Dietary Spirulina platensis Phycocyanin

This study investigated the dietary effect of Spirulina platensis phycocyanin (SPC) on growth performance (body weight (BW), body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR)) at starter, grower, and finisher stages, intestinal histomorphology, serum biochemical parameters, inflammatory and antioxidant indices, and proinflammatory cytokines (tumor necrosis factor-α and caspase-3) immune expression in broiler chickens. In total, 250 one-day-old chicks (Ross 308 broiler) were randomly allotted to five experimental groups (5 replicates/group, 10 chicks/replicate) and fed basal diets supplemented with five levels of SPC (0, 0.25, 0.5, 0.75, and 1 g kg–1 diet) for 35 days. Compared with SPC0 treatment, different SPC levels increased the overall BW and BWG without affecting the total feed consumption. However, the FCR decreased linearly with an increase in supplementation level. The serum levels of total proteins, albumin, globulins, and growth hormone increased linearly by increasing levels of SPC supplementation. Further, SPC supplementation increased the thyroxin hormones without affecting serum glucose and leptin levels. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) values decreased in broilers fed SPC0.250 and SPC1 diets. Triglycerides (TG) decreased in SPC0.25-, SPC0.75-, and SPC1-treated groups. Though antioxidant enzyme activities (total antioxidant capacity, catalase, and superoxide dismutase) increased linearly and quadratically, malondialdehyde (MDA) decreased linearly by increasing the SPC level. There was no effect on serum proinflammatory cytokines IL1β levels. Immunolabelling index of caspase-3 and tumor necrosis factor-α (TNF-α) were downregulated by SPC supplementation. The intestinal histomorphology is represented by increased villus height, the villus height to crypt depth ratio, and numbers of goblet cells in different sections of the small intestine. In conclusion, SPC supplementation is beneficial in broiler chicken diets due to its growth-promoting, antioxidant, and anti-inflammatory properties.

Effects of different levels of spirulina (Arthrospira platensis) supplementation on productive performance, nutrient digestibility, blood metabolites, and meat quality of growing Najdi lambs

In a 90-day study, 32 growing lambs aged 3 months were utilized to evaluate the effects of various levels of spirulina dietary supplement on productive performance, nutritional digestibility, and meat quality in growing Najdi lambs. The lambs were put into 4 groups of 8 lambs each at random. The diet consisted of a total mixed ration (TMR) without spirulina (CONT), and the TMR diet supplemented with spirulina at the levels of 2 ppm (SPP2), 4 ppm (SPP4), and 8 ppm (SPP8). The treatment groups, especially SPP8, showed a significant (p < 0.05) increase in body weight and average daily gain (p < 0.05) compared to the CONT group. Dry matter intake and acid detergent fiber were also significantly (p ≤ 0.05) higher in SPP8 compared to other treated groups and CONT. The N absorption, N retention, and percentage of N digestibility coefficient were greater (P < 0.05) in lambs in the treatment groups than in the CONT. Blood biochemistry variables were not significantly (p ≤ 0.05) affected by the treatments, with the exception of the serum concentration of triglyceride and bilirubin. Carcass profile and meat quality, including back fat, body wall fat, and cooking loss, were increased significantly (p ≤ 0.05) with dietary spirulina. From the results of the present study, it was concluded that spirulina dietary supplementation at the level of 8 ppm increased weight gain, nutritional digestibility, nitrogen utilization, and meat composition in growing Najdi lambs.

Role of Different Growth Enhancers as Alternative to In-feed Antibiotics in Poultry Industry

The poultry industry has grown so fast alongside the irrational use of antibiotics to maximize profit and make the production cost-effective during the last few decades. The rising and indiscriminate use of antibiotics might result in the deposition of residues in poultry food products and in the development of resistance to these drugs by microorganisms. Therefore, many diseases are becoming difficult to treat both in humans and animals. In addition, the use of low-dose antibiotics as growth enhancer results in antibiotic residues in food products, which have detrimental effects on human health. On the other hand, many studies have shown that antibiotics administered to poultry and livestock are poorly absorbed through the gut and usually excreted without metabolism. These excreted antibiotics eventually accumulate in the environment and enter the human food chain, resulting in the bioaccumulation of drug residues in the human body. In this regard, to find out alternatives is of paramount importance for the production of safe meat and egg. Therefore, in recent years, much research attention was disarticulated toward the exploration for alternatives to antibiotic as in-feed growth enhancers after its ban by the EU. As a result, probiotics, prebiotics, phytobiotics, spirulina, symbiotic, and their combination are being used more frequently in poultry production. Feed additives therefore gained popularity in poultry production by having many advantages but without any residues in poultry products. In addition, numerous studies demonstrating that such biological supplements compete with antimicrobial resistance have been conducted. Therefore, the purpose of this review article was to highlight the advantages of using biological products instead of antibiotics as poultry in-feed growth enhancers to enhance the production performance, reduce intestinal pathogenic bacteria, and maintain gut health, potentiating the immune response, safety, and wholesomeness of meat and eggs as evidence of consumer protection, as well as to improve the safety of poultry products for human consumption.

Synergistic effect of Spirulina platensis and selenium nanoparticles on growth performance, serum metabolites, immune responses, and antioxidant capacity of heat-stressed broiler chickens

This study examined the effects of dietary Spirulina platensis (SP) at levels of 0, 5, and 10 g.kg^-1 and selenium nanoparticles (SeNPs) at 0, 0.1, and 0.2 mg.kg^-1, individually and in combination, on heat-stressed broiler chickens for 5 weeks. Four hundred fifty one-day-old Ross-308 chicks were allocated to 9 dietary groups with 5 replicates (10 chicks each). The control diet was consisted of corn-soybean-based basal diet. The obtained results displayed a significant increase in final body weight (p = 0.005) and weight gain during the periods from 22 to 35 days (p = 0.002) and 1 to 35 days (p = 0.005) in birds fed supplemented diets compared to those fed control diet, with the highest being in birds fed with both 10 g SP and 0.1 mg SeNPs. Feed conversion ratio was also improved in birds fed supplemented compared to control group. Dietary supplements significantly improved carcass dressing (p < 0.001), carcass yield (p = 0.001) percentages, and blood lipid profile. Blood triiodothyronine was higher (p = 0.005) with all treated diets except that contain 5 g SP compared to the control, with the highest being in birds fed diet contains 5 g SP + 0.2 mg SeNPs. Immunoglobulin subclasses IgG, IgM, and IgA were higher in birds fed supplemented diets compared to the control group. Antibody titers to Newcastle disease, avian influenza, and infectious bursal disease were numerically increased with dietary supplementation compared to the control group. Dietary treatments increased (p < 0.001) glutathione peroxidase and superoxide dismutase (SOD) levels, except diet contains 5 g SP for SOD level and decreased (p < 0.001) malondialdehyde level. It is concluded that dietary inclusion of SP and SeNPs, particularly their combination at levels 5 g SP plus 0.2 mg SeNPs kg^-1 and 10 g SP plus 0.1 mg SeNPs kg^-1, improved growth performance, carcass yield, immunity, and antioxidant capacity of heat-stressed broilers.

Dietary microalgae on poultry meat and eggs: explained versus unexplained effects

Different types and sources of microalgae are used to feed broiler chickens and laying hens. This review provides a concise update on various impacts of feeding these novel ingredients on physical, chemical, and nutritional attributes of the resultant meat and eggs. Some of the observed effects may be associated with biochemical and molecular mechanisms derived from unique chemical compositions and nutritional values of microalgae. However, the full potential and the accurate mechanism of microalgae in producing health-promoting poultry foods remain to be explored.

Effects of Spirulina (Arthrospira platensis) as a drinking water supplement during cyclical chronic heat stress on broiler chickens: Assessing algal composition, production, stress, health and immune-biochemical indices

Spirulina, the blue green algae is considered to exhibit multifaceted benefits on both human health and animal production. Three hundred sixty day old unsexed broiler chicks of CARIBROVISHAL strain were assigned to five treatment groups each comprising nine replicates of 8 chicks. The experiment was carried out during the hot humid summer season (Mid-April to May) under deep litter rearing system with uniform managemental conditions. Birds were administered orally with Spirulina through drinking water in the morning (06:00-12:00 PM) on daily basis throughout the experimental period at 5, 10, 15 and 20 gL^-1 concentration. Spirulina supplementation neither improved nor compromised production performance of broilers reared during hot climatic condition. Results based on one way analysis of variance indicated a significant effect on haemoglobin and total red blood cell count. Serum lipid content and transaminases were reduced, while serum protein concentration was higher (P < 0.01) in the groups administered with 15 and 20 gL^-1 of Spirulina. The extent of imparting shank pigmentation was improved in all the supplemented groups. Cell mediated and humoral immunity against Phytoheamagglutunin-P and Newcastle disease vaccination respectively were maximized (P < 0.05) at 20 gL^-1. These findings provide direct evidence of dose-related modulation of production, physiological and immunological attributes by Spirulina engendering its further investigation as a potential source of drinking water supplement for stress alleviation in broilers. From the results, it may concluded that Spirulina can be incorporated at 15 or 20 gL^-1 for achieving optimal improvement of health and welfare attributes in broilers reared during hot summer without compromising production.

Antimicrobial and Antioxidant Potential of Scenedesmus obliquus Microalgae in the Context of Integral Biorefinery Concept

Small-scale photobioreactors (PBRs) in the inoculum stage were designed with internal (red or green) and external white LED light as an initial step of a larger-scale installation aimed at fulfilling the integral biorefinery concept for maximum utilization of microalgal biomass in a multifunctional laboratory. The specific growth rate of Scenedesmus obliquus (Turpin) Kützing biomass for given cultural conditions was analyzed by using MAPLE software. For the determination of total polyphenols, flavonoids, chlorophyll “a” and “b”, carotenoids and lipids, UHPLC-HRMS, ISO-20776/1, ISO-10993-5 and CUPRAC tests were carried out. Under red light growing, a higher content of polyphenols was found, while the green light favoured the flavonoid accumulation in the biomass. Chlorophylls, carotenoids and lipids were in the same order of magnitude in both samples. The dichloromethane extracts obtained from the biomass of each PBR synergistically potentiated at low concentrations (0.01–0.05 mg/mL) the antibacterial activity of penicillin, fluoroquinolones or oregano essential oil against the selected food-borne pathogens (Staphylococcus aureus, Escherichia coli and Salmonella typhimurium) without showing any in vitro cytotoxicity. Both extracts exhibited good cupric ion-reducing antioxidant capacity at concentrations above 0.042–0.08 mg/mL. The UHPLC-HRMS analysis revealed that both extracts contained long chain fatty acids and carotenoids thus explaining their antibacterial and antioxidant potential. The applied engineering approach showed a great potential to modify microalgae metabolism for the synthesis of target compounds by S. obliquus with capacity for the development of health-promoting nutraceuticals for poultry farming.

Laser Environmental Enrichment and Spirulina Algae Improve Broiler Growth Performance and Alter Myogenic Gene Expression and pectoralis major Dimensions

Sustainability in poultry production is evident in efforts to reduce inputs and a focus on bird welfare and livability. Dietary protein alternatives to traditional sources such as soybean meal aim to meet or exceed efficiency benchmarks and be cost-effective. Environmental enrichment encouraging activity may reduce the occurrence of the predominant breast muscle myopathy, woody breast (WB); interventions to minimize muscle damage and economic loss have yet to be established. The study objectives were to maintain or improve broiler performance and breast quality through environmental enrichment and partially replacing dietary soybean meal with Spirulina. Twelve hundred Ross 708 broilers were randomly assigned to enrichment (LASER; laser enrichment, or CON; no laser enrichment) and diet (algae; 2.5% Spirulina algae, or control) in a 2 × 2 factorial design for 49 days. The same 70 randomly selected birds were examined for contact dermatitis wk 1–6. Breast width was measured weekly on 200 growing broilers beginning on d22. On d42 and 49 slaughter, WB score was assigned using a tactile 0–3 scale and the right breast filet was weighed (n = 200). RNA isolated from 30 breast muscle samples each at d42 and 49 was analyzed using real-time qPCR. Laser enrichment increased body weight at all timepoints (d49: 0.148 kg, P &lt; 0.001). Feed conversion ratio was improved in LASER-enriched birds by 3 points in the starter period (P = 0.003). Breast width was increased at all timepoints in LASER-enriched birds compared to CON (d49: 0.47 cm, P &lt; 0.001). Algae inclusion increased body weight at d28 (0.059 kg, P = 0.005). At d42, 12% more LASER-enriched WB scores were 0 (normal) compared to CON, and at d49, 15% more enriched scores were 0. At d42, 5% more algae-fed broiler scores were 0 compared to control. LASER-enriched broiler breast tissue showed upregulated expression of myogenin, muscle regulatory factor 4, insulin-like growth factor 1, and myostatin compared to CON (P &lt; 0.01). Both laser enrichment and algae inclusion improved broiler performance without negatively impacting environmental or physiological outcomes. LASER enrichment decreased severity of WB score and positively shifted myogenic gene expression in the breast muscle at slaughter.

Bioremediation role of Spirulina platensis against deltamethrin-mediated toxicity and its chemical residues in chicken meat

Deltamethrin (DM) is a synthetic pyrethroid insecticide commonly used in veterinary and agriculture. However, both animal and human exposure are associated with hepatorenal toxicity. Our experimental goal was to assess the protective effects of Spirulina platensis (SP) against DM-induced hepatorenal injury, growth performance, meat chemical composition, and its residues in meat, liver, and skin of broiler chickens. Sixty 1-day-old Cobb broiler chicks were assigned to 4 experimental groups; each was divided into 3 replicates with five chicks each; the 1st group received basal diet alone (control), 2nd group supplemented with SP 20 g/kg diet, 3rd group supplemented with DM 300 mg/kg diet, and 4th group supplemented with DM and SP diet. All groups have received the treatment for 35 days. DM, decreased body weight, weight gain, and increased feed conversion rate. DM showed a significant increase in ALT, AST, urea, creatinine, and MDA and a significant decrease in SOD, and GSH levels. Also, SP significantly reduced DM levels in meat, skin, and liver with a reduction 63.01, 63.00, and 62.90 %, respectively. The DM intoxicated group showed a significant decrease in protein and a marked increase in fat, cholesterol, and triglycerides when compared to the control group. Histopathological changes were also recorded. Dietary SP improved these parameters. Dietary inclusion of SP can be recommended due to the protective effects on DM-induced toxicity in broiler chickens.

Adaptation of Livestock to New Diets Using Feed Components without Competition with Human Edible Protein Sources-A Review of the Possibilities and Recommendations

Simple Summary

Livestock feed contains components that can also be consumed by humans, which may become less available for livestock. Proteins are such components that may become less available for livestock feed. This review focuses on using alternative protein sources in feed. We may expect protein efficiency problems and we discuss how these could be solved using a combination of alternative protein sources and animal breeding. We make recommendations for the use and optimization of novel protein sources.

Abstract

Livestock feed encompasses both human edible and human inedible components. Human edible feed components may become less available for livestock. Especially for proteins, this calls for action. This review focuses on using alternative protein sources in feed and protein efficiency, the expected problems, and how these problems could be solved. Breeding for higher protein efficiency leading to less use of the protein sources may be one strategy. Replacing (part of) the human edible feed components with human inedible components may be another strategy, which could be combined with breeding for livestock that can efficiently digest novel protein feed sources. The potential use of novel protein sources is discussed. We discuss the present knowledge on novel protein sources, including the consequences for animal performance and production costs, and make recommendations for the use and optimization of novel protein sources (1) to improve our knowledge on the inclusion of human inedible protein into the diet of livestock, (2) because cooperation between animal breeders and nutritionists is needed to share knowledge and combine expertise, and (3) to investigate the effect of animal-specific digestibility of protein sources for selective breeding for each protein source and for precision feeding. Nutrigenetics and nutrigenomics will be important tools.

A viewpoint on the use of microalgae as an alternative feedstuff in the context of pig and poultry feeding-a special emphasis on tropical regions

With the current increase in meat and animal products consumption, there is a need to make production systems more sustainable. The use of microalgae in monogastric feeds, replacing widely used conventional feedstuffs such corn and soybean, can be a solution to overcome this problem. Several studies have shown promising results in the use of microalgae in feeding of both pigs and poultry. However, there are several important constraints associated to the production of microalgae. Such constraints are particularly limiting in the context of tropical regions. Research and scientific development on microalgae production systems are thus essential so that may be widely used in monogastric feeding. Herein, we conduct an overview of the major findings in the use of microalgae in the context of monogastric feeding and analyse the major constraints associated to its production and use, particularly in the specific context of tropical regions.

Algae-based feed ingredient protects intestinal health during Eimeria challenge and alters systemic immune responses with differential outcomes observed during acute feed restriction

Compounds in microalgae-derived feed ingredients in poultry diets may improve intestinal physiology and immunity to protect against damage induced by physiological and pathogen challenges, but mechanisms are examined sparingly. The study objective was to evaluate changes to intestinal morphology, permeability, and systemic immunity in broilers fed a proprietary microalgae ingredient during 2 separate challenge studies. In study 1, two replicate 28 d battery cage trials used 200 Ross 308 broilers each (n = 400) fed a control diet ± 0.175% algae ingredient. Half of the birds were subjected to a 12 h feed restriction challenge and fluorescein isothiocyanate dextran (FITC-D) intestinal permeability assay on d 28. Study 2 used 800 broilers randomly assigned to the same dietary treatments and housed in floor pens for 42 d. At d 14, intestine and spleen samples were collected from 10 birds/ diet. Half of the remainder was orally inoculated with 10X Coccivac-B52 vaccine in a 2 × 2 factorial treatment design (diet and Eimeria inoculation). The FITC-D assay was conducted at 1, 3, 7, and 14 d post-inoculation (pi) while intestinal and spleen samples were collected at 3, 7, 14, and 28 dpi for histomorphology and flow cytometric immune cell assessment. Study 1 validated intestinal leakage via FITC-D absorbance induced by feed restriction but showed no algae-associated protective effects. In study 2, algae preserved intestinal integrity during coccidiosis (P = 0.04) and simultaneously protected jejunal villus height as early as 7dpi (P < 0.0001), whereas intestinal damage resolution in control birds did not occur until 14 dpi. Algae inclusion increased splenic T cells in unchallenged broilers at d 14 by 29.6% vs. control (P < 0.0001), specifically γδ T cell populations, without impacting performance (P < 0.03). During Eimeria challenge, splenic T cells in algae-fed birds did not show evidence of recruitment to peripheral tissues, while control birds showed a 16.7% reduction compared to their uninoculated counterparts from 3 to 7 dpi (P < 0.0001). This evidence suggests the algae ingredient altered the immune response in a manner that reduced recruitment from secondary lymphoid organs in addition to protecting intestinal physiology.

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.

Dietary supplementation of extracts of red sea weed (Kappaphycus alvarezii) improves growth, intestinal morphology, expression of intestinal genes and immune responses in broiler chickens

BACKGROUND

Effects of supplementation of dried alkaline (referred to as MVP1) and aqueous (referred to as PBD1) extracts of Kappaphycus alvarezii, were evaluated in broiler (Vencobb 400) chickens (1-35 days post-hatch). In experiment I, each of the seven diets (basal diet with three levels (0.5, 1.5 or 5.0 g kg^-1 diet) of MVP1 or PBD1 and a negative control was fed to 12 pen replicates containing five birds in each. In experiment II, each of three diets [a negative control, and PBD1 at two levels (1.0 or 1.5 g kg^-1 diet)] was fed to 16 pen replicates of five chicks in each.

RESULTS

Concentrations of total phenolics, phycobillins and free radical scavenging activity were higher (P < 0.01) whereas carrageenan was lower in PBD1 than in MVP1. In the experiment I, PBD1 at 1.5 g kg^-1 diet improved (P < 0.05) body weight (BW) (7.11% higher). In the experiment II, both the treatments improved (P < 0.01) BW (9.18% and 8.47%, respectively) compared to the control. The group fed with PBD1@ 1.0 g kg^-1 had higher (P < 0.05) haemagglutination inhibition titre, expression of intestinal claudin 2, TLR2A, NOD1, avian beta defensin 4, interleukin 2 and interleukin 6 genes than control. Treatments did not influence feed efficiency or levels of most of the antioxidant enzymes. Villus width and crypt depth were significantly higher in the group fed with 1.5 g kg^-1 of PBD1.

CONCLUSION

Supplementing dried aqueous extract of K. alvarezii at 1 g kg^-1 diet may be an effective strategy to increase growth and immunity in broiler chickens. © 2020 Society of Chemical Industry.

Influence of dietary Chlorella vulgaris and carbohydrate-active enzymes on growth performance, meat quality and lipid composition of broiler chickens

Herein, we investigated the effect of Chlorella vulgaris as ingredient (10% of incorporation) in broiler diets, supplemented or not with 2 formulations of Carbohydrate-Active enZymes (CAZymes; Rovabio Excel AP and a mixture of recombinant CAZymes, composed by an exo-β-glucosaminidase, an alginate lyase, a peptidoglycan N-acetylmuramic acid deacetylase and a lysozyme), on growth performance, meat quality, fatty acid composition, oxidative stability, and sensory traits. One hundred twenty 1-day-old Ross 308 male birds were randomly assigned to one of the 4 experimental diets (n = 30): corn-soybean meal–basal diet (control), basal diet with 10% C. vulgaris (CV), CV supplemented with 0.005% of a commercial CAZyme cocktail (Rovabio Excel AP), (CV + R), and CV supplemented with 0.01% of a 4-CAZyme mixture previously selected (CV + M) during the experimental period lasted from day 21 to day 35. Body weight gain and feed conversion rate of broilers were not affected by C. vulgaris but digesta viscosity increased more than 2-fold (P < 0.001) relative to the control. In addition, neither cooking loss, shear force, juiciness, flavor nor off-flavor was impaired by dietary treatments (P > 0.05). By contrast, the dietary C. vulgaris increased tenderness, yellowness (b∗) and total carotenoids in breast and thigh meats. However, no additional protective effect against lipid oxidation was observed in meat with the inclusion of microalga. Chlorella vulgaris, independently of CAZymes, had a minor impact on meat fatty acid composition but improved the proportion of some beneficial fatty acids. In summary, our data indicate a slight improvement of broiler meat quality and lipid nutritional value, without impairment of broilers' growth performance, thus supporting the usefulness of this microalga in poultry diets, up to this high level of incorporation. By contrast, the selected CAZyme mixtures used do not significantly improve the release of microalga nutrients in poultry diets, through the disruption of microalga cell wall, which warrants further research.

Effect of dietary inclusion of Spirulina on production performance, nutrient digestibility and meat quality traits in post-weaning piglets

The effect of Spirulina (Arthrospira platensis), individually or in combination with two commercial carbohydrases, in piglet diets was assessed on growth performance, nutrient digestibility and meat quality traits. Forty post-weaned male piglets from Large White × Landrace sows crossed with Pietrain boars with an initial live weight of 12.0 ± 0.89 kg were used. Piglets were assigned to one of four dietary treatments (n = 10): cereal and soya bean meal base diet (control), base diet with 10% Spirulina (SP), SP diet supplemented with 0.005% Rovabio^® Excel AP (SP + R) and SP diet supplemented with 0.01% lysozyme (SP + L). Animals were slaughtered after a 4-week experimental period. Growth performance was negatively affected by the incorporation of Spirulina in the diets, with an average decrease of 9.1% on final weight, in comparison with control animals. Total tract apparent digestibility (TTAD) of crude protein was higher (p < .05) in the control group than in other groups. In addition, lysozyme increased TTAD of crude fat and acid detergent fibre, relative to the SP and control groups, respectively. In addition, the incorporation of Spirulina, individually and supplemented with enzymes, did not impair meat quality traits. Surprisingly, no protective effect against lipid oxidation was observed with the inclusion of Spirulina in pork after 7 days of storage. This study indicates that growth performance of post-weaning piglets was impaired by the incorporation of 10% Spirulina in the diets, which is mediated by an increase in digesta viscosity and a lower protein digestibility, as a consequence of the resistance of microalga proteins to the action of endogenous peptidases. In addition, it also indicates that lysozyme, in contrast to Rovabio^® Excel AP, is efficient in the degradation of Spirulina cell wall in piglet's intestine. However, the digestion of proteins liberated by Spirulina cell wall disruption is still a challenge.

Impact of dietary incorporation of Spirulina (Arthrospira platensis) and exogenous enzymes on broiler performance, carcass traits, and meat quality

This study assessed the effect of Spirulina (Arthrospira platensis), individually and in combination with exogenous enzymes, on growth performance, carcass traits, and meat quality of broiler chickens. One hundred and twenty Ross 308 male chickens were allocated into 40 battery brooders, with 3 birds per cage, and fed ad libitum a corn-based diet during the first 21 D of the trial. The experimental period lasted from day 21 to 35, during which birds were fed 4 different diets: a corn-soybean basal diet, taken as the control group, a basal diet containing 15% Spirulina (MA), a basal diet containing 15% Spirulina plus 0.005% Rovabio Excel AP (MAR), and a basal diet containing 15% Spirulina plus 0.01% lysozyme (MAL). Body weight gain (P < 0.001) and feed conversion rate (P < 0.001) were improved in control chickens, when compared with those fed with Spirulina. In addition, Spirulina increased the length of duodenum plus jejunum in relation to the other treatment (P < 0.01). Chickens on the MAL diet showed a considerable increase in digesta viscosity (P < 0.05) compared with the control group. Breast and thigh meats from chickens fed with Spirulina, with or without the addition of exogenous enzymes, had higher values of yellowness (b*) (P < 0.001), total carotenoids (P < 0.001), and saturated fatty acids (P < 0.001), whereas n-3 polyunsaturated fatty acid (P < 0.01) and α-tocopherol (P < 0.001) decreased, when compared with the control. In conclusion, the incorporation of 15% Spirulina in broiler diets, individually or combined with exogenous enzymes, reduced birds' performance through a higher digesta viscosity, which is likely associated with the gelation of microalga indigestible proteins. In addition, cell wall of Spirulina was successfully broken by the addition of lysozyme, but not by Rovabio Excel AP. Therefore, we anticipate that the combination of lysozyme with an exogenous specific peptidase could improve the digestibility of proteins from this microalga and avoid their detrimental gelation.

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.

Effect of dietary Spirulina (Arthrospira) platensis on the growth performance, antioxidant enzyme activity, nutrient digestibility, cecal microflora, excreta noxious gas emission, and breast meat quality of broiler chickens

This study examined the effects of dietary Spirulina (Arthrospira) platensis supplementation on growth performance, antioxidant enzyme activity, nutrient digestibility, cecal microflora, excreta noxious gas emission, organ weight and breast meat quality in broiler chickens. In total, 800 Ross 308 male broiler chickens (1-d-old) were randomly divided into 5 dietary treatments with 10 replicate cages (16 birds/replicate) per treatment for 5 wk. The dietary treatments were a control basal diet without Spirulina or with 0.25, 0.5, 0.75, or 1.0% Spirulina. Body weight gain, feed conversion, and/or European production efficiency index improved linearly with supplementation of Spirulina during d 8 to 21, 22 to 35, and overall d 1 to 35 (P < 0.05). Dietary Spirulina supplementation caused a significant increase in the serum enzyme activity of superoxide dismutase and glutathione peroxidase (linear, P < 0.05). Apparent total tract digestibility of dry matter and nitrogen showed a linear increase in Spirulina supplementation (P < 0.05). Cecal Lactobacillus count linearly increased and excreta ammonia gas emission linearly decreased, as dietary Spirulina supplementation increased (P < 0.05). There were no significant effects on relative organ weight and breast meat quality of broilers fed with Spirulina diets; however, 7 d drip loss linearly decreased in treatment groups fed with Spirulina (P < 0.05). These results indicate that adding Spirulina to the diet of broilers can improve antioxidant enzyme activity, dry matter and nitrogen digestibility, cecal Lactobacillus population, excreta ammonia gas emission, and 7 d drip loss of breast meat. In addition, dietary inclusion of 1.0% Spirulina powder might provide a good alternative to improve broiler chicken production.

Apparent metabolisable energy and amino acid digestibility of microalgae Spirulina platensis as an ingredient in broiler chicken diets

1. This work investigates the apparent metabolisable energy (AME), its nitrogen-corrected form (AMEn) and amino acid (AA) digestibility coefficients of the microalgae Spirulina platensis as an ingredient in broiler chicken diets. 2. One group of birds was fed with a basal control diet (BD), and another was fed with a test diet composed of the BD with the addition of the microalgae at a proportion of 200 g/kg. AME and AMEn were assessed by total excreta collection and indigestibility analysis using acid-insoluble ash (AIA) as a marker. 3. The microalgae comprised 888.0 g/kg dry matter (DM), 18.42 MJ/kg gross energy, 514.7 g/kg crude protein, 9.9 g/kg ether extract, 10.6 g/kg crude fibre, 94.4 g/kg ash, 3.1 g/kg Ca and 11.0 g/kg P. 4. The values obtained for AME (13.48 MJ/kg DM) and AMEn (11.72 MJ/kg DM) were higher (p < 0.01) than those obtained using the AIA method (9.39-8.29 MJ/kg DM). The microalgae ileal digestibility coefficients were 0.80 ± 0.04 and 0.78 ± 0.04 for essential and non-essential AA, respectively. 5. Overall, the metabolisable energy content and digestibility of AA for S. platensis indicated that the microalgae are potentially an alternative nutrient source for broilers. The AIA method underestimated AME and AMEn in comparison to the total excreta collection method.