Effects of Inclusion of Schizochytrium spp. and Forage-to-Concentrate Ratios on Goats' Milk Quality and Oxidative Status

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.

Use of green microalgae Chlorella as a nutritional supplement to support oocyte and embryo production in goats

This study aimed to evaluate the use of green microalgae as a nutritional supplement for oocyte and embryo production in goats. Two experiments were performed on adult goats to obtain oocytes (EVO; n = 14) and in vivo embryos (IVD; n = 14). In both, the donors were divided into control (n = 7) and Chlorella (n = 7) groups. All goats received a base diet, and donors were orally supplemented with Chlorella pyrenoidosa (CH) in the Chlorella groups. For EVO, donors received 10 g CH for 14 days, and for IVD, 20 g CH was given for six days before embryo recovery. In EVO and IVD, food intake in the CH group was comparatively low, and it showed relatively high subcutaneous adipose deposition. In addition, the CH group exhibited an increase in triglyceride, cholesterol, and plasma glucose levels. In IVD, a significant increase in peripheral glutathione peroxidase levels was noticed. In EVO, the CH group showed relatively large follicular size and an increase in intrafollicular levels of triglycerides, glucose, and glutathione peroxidase. No differences were observed in the oocyte collected, and CH oocytes showed a low intensity of MitoTracker fluorescence (MT). In IVD, the CH group had a high proportion of transferable embryos, and these structures exhibited high fluorescence intensities for MT and H2DCFDA probes. We concluded that under these conditions, CH did not enhance the quality of the recovered oocytes. However, a daily dose of 20 g CH improved the quality of embryos and stimulated their mitochondrial functionality.

Effect of Spirulina Dietary Supplementation in Modifying the Rumen Microbiota of Ewes

Supplementing ruminant diets with microalgae, may prove an effective nutritional strategy to manipulate rumen microbiota. Forty-eight ewes were divided into four homogenous groups (n = 12) according to their fat-corrected milk yield (6%), body weight, age, and days in milk, and were fed individually with concentrate, alfalfa hay, and wheat straw. The concentrate of the control group (CON) had no Spirulina supplementation, while in the treated groups 5 (SP5), 10 (SP10), and 15 g (SP15) of Spirulina were supplemented as an additive in the concentrate. An initial screening using metagenomic next-generation sequencing technology was followed by RT-qPCR analysis for the targeting of specific microbes, which unveiled the main alterations of the rumen microbiota under the Spirulina supplementation levels. The relative abundance of Eubacterium ruminantium and Fibrobacter succinogenes in rumen fluid, as well as Ruminococcus albus in rumen solid fraction, were significantly increased in the SP15 group. Furthermore, the relative abundance of Prevotella brevis was significantly increased in the rumen fluid of the SP5 and SP10 groups. In contrast, the relative abundance of Ruminobacter amylophilus was significantly decreased in the rumen fluid of the SP10 compared to the CON group, while in the solid fraction it was significantly decreased in the SP groups. Moreover, the relative abundance of Selenomonas ruminantium was significantly decreased in the SP5 and SP15 groups, while the relative abundance of Streptococcus bovis was significantly decreased in the SP groups. Consequently, supplementing 15 g Spirulina/ewe/day increased the relative abundance of key cellulolytic species in the rumen, while amylolytic species were reduced only in the solid fraction.

Schizochytrium spp. Dietary Supplementation Modulates Immune-Oxidative Transcriptional Signatures in Monocytes and Neutrophils of Dairy Goats

The high propensity of dietary polyunsaturated fatty acids (PUFA) to oxidation can induce a cascade of cellular immune-oxidative imbalances. On the other hand, PUFA, namely docosapentaenoic acid (ω6-DPA) and docosahexaenoic acid (DHA) can exert immunomodulatory effects by suppressing a pro-inflammatory response. Thus, the objective of this study was to investigate the effect of dietary supplementation with Schizochytrium spp. levels, rich in both ω6-DPA and DHA on the transcriptional profiling of genes involved in oxidative homeostasis and innate immunity of dairy goats' monocytes and neutrophils. Twenty-four dairy goats were divided into four homogeneous sub-groups; the diet of the control group (CON) had no Schizochytrium spp. while those of the treated groups were supplemented daily with 20 (ALG20), 40 (ALG40), and 60 (ALG60) g/goat/day. The mRNA levels of MGST1 in neutrophils were downregulated (p = 0.037), while in monocytes, SOD2 and SOD3 were downregulated (p = 0.010 and p = 0.044, respectively) in ALG60 compared to the CON group. GPX2 mRNA levels were downregulated (p = 0.036) in ALG20 and ALG60 compared to the CON group in neutrophils. NOX1 was upregulated (p = 0.043) in the neutrophiles of ALG60-goats. NOX2 was upregulated (p = 0.042) in the monocytes of ALG40-fed goats, while higher (p = 0.045) levels were also found in the ALG60 group in neutrophils. The mRNA levels of COX2 were downregulated (p = 0.035) in monocytes of the ALG40 and ALG60 groups. The mRNA levels of PTGER2 were also downregulated (p = 0.004) in monocytes of Schizochytrium-fed goats, while in neutrophils, significant downregulation (p = 0.024) was only found for ALG60 compared to the CON group. ALOX5AP mRNA levels were significantly decreased (p = 0.033) in ALG60 compared to the CON group in monocytes. LTA4H mRNA levels were increased (p = 0.015) in ALG60 compared to ALG20 and ALG40 groups in monocytes, while in neutrophils, a significant downregulation (p = 0.028) was observed in ALG20 compared to the CON group. The inclusion of more than 20 g Schizochytrium spp./day in goats' diet induced imbalances in mechanisms that regulate the antioxidant system, while downregulated the expression of pro-inflammatory pathways in monocytes and neutrophils.

Effects of capsicum oleoresin supplementation on rumen fermentation and microbial abundance under different temperature and dietary conditions in vitro

This study aimed to determine the effect of capsicum oleoresin (CAP) on rumen fermentation and microbial abundance under different temperature and dietary conditions in vitro. The experimental design was arranged in a 2 × 2 × 3 factorial format together with two temperatures (normal: 39°C; hyperthermal: 42°C), two forage/concentrate ratios (30:70; 70:30), and two CAP concentrations in the incubation fluid at 20 and 200 mg/L with a control group. Regarding the fermentation characteristics, high temperature reduced short-chain fatty acids (SCFA) production except for molar percentages of butyrate while increasing acetate-to-propionate ratio and ammonia concentration. The diets increased total SCFA, propionate, and ammonia concentrations while decreasing acetate percentage and acetate-to-propionate ratio. CAP reduced acetate percentage and acetate-to-propionate ratio. Under hyperthermal condition, CAP could reduce acetate percentage and increase acetate-to-propionate ratio, lessening the negative effect of high heat on SCFA. Hyperthermal condition and diet altered the relative abundance of microbial abundance in cellulose-degrading bacteria. CAP showed little effect on the microbial abundance which only increased Butyrivibrio fibrisolvens. Thus, CAP could improve rumen fermentation under different conditions, with plasticity in response to the ramp of different temperature and dietary conditions, although hardly affecting rumen microbial abundance.

The Effect of Dietary Inclusion of Microalgae Schizochytrium spp. on Ewes’ Milk Quality and Oxidative Status

An unprecedented challenge for nutritionists arises during the 21st century in order to produce highly nutritious and functional food which promotes human health. Polyunsaturated fatty acids (PUFA) that are highly contained in microalgae have broadly been confirmed for preventing cardiovascular diseases and regulating immune-oxidative status. However, their optimum dietary inclusion level needs to be defined since PUFA are prone to oxidation. For this purpose, 24 cross-bred dairy ewes, were separated into four groups (n = 6) and were fed with different levels of microalgae Schizochytrium spp. [0 (CON, no microalgae), 20 (SC20), 30 (SC30) and 40 (SC40) g/ewe/day] for 60 days. The results showed that although the production parameters were not impaired, milk fat content was decreased in medium and high-level supplemented groups while protein content was suppressed only for the medium one. Concerning the fatty acids (FA) profile, the proportions of C_14:0, trans C_18:1, trans-11 C_18:1, cis-9, trans-11 C_18:2, trans-10, cis-12 C_18:2, C_20:5 (EPA), C_22:5n-6 (DPA), C_22:6n-3 (DHA), the total ω3 FA and PUFA were significantly increased, while those of C_18:0, cis-9 C_18:1 and C_18:2n-6c were decreased in the milk of treated ewes. Additionally, in the S40 group an oxidative response was induced, observed by the increased malondialdehyde (MDA) levels in milk and blood plasma. In conclusion, the dietary inclusion of 20 g Schizochytrium spp./ewe/day, improves milks’ fatty acid profile and seems to be a promising way for producing ω3 fatty acid-enriched dairy products.

The Effect of Forage-to-Concentrate Ratio on Schizochytrium spp.-Supplemented Goats: Modifying Rumen Microbiota

Simple Summary

The in-depth understanding of rumen functions would be the greatest achievement of animal nutritionists. Hence, plenty of feed additives and various nutritional techniques are studied in modifying and understand the rumen habitat. In our study, we investigated the effect of alteration of the forage: concentrate (F:C) ratio in goats supplemented with the microalgae Schizochytrium spp. on rumen microbiota communities and enzymatic activity. Our results suggested that even though specific microbes’ abundance was altered, their corresponding enzymatic potential did not follow the same trend. Nonetheless, principal ruminal functions such as ammonia accumulation, fibrolytic activity, and degradation rate of specific fatty acids were also modified due to dietary intervention.

Abstract

The inclusion of feed additives and the implementation of various nutritional strategies are studied to modify the rumen microbiome and consequently its function. Nevertheless, rumen enzymatic activity and its intermediate products are not always matched with the microbiome structure. To further elucidate such differences a two-phase trial using twenty-two dairy goats was carried out. During the first phase, both groups (20HF n = 11; high forage and 20HG n = 11; high grain) were supplemented with 20 g Schizochytrium spp./goat/day. The 20HF group consumed a diet with a forage:concentrate (F:C) ratio of 60:40 and the 20HG-diet consisted of a F:C = 40:60. In the second phase, the supplementation level of Schizochytrium spp. was increased to 40 g/day/goat while the F:C ratio between the two groups were remained identical (40HF n = 11; high forage and 40HG n = 11; high grain). By utilizing a next-generation sequencing technology, we monitored that the high microalgae inclusion level and foremost in combination with a high grains diet increased the unmapped bacteria within the rumen. Bacteroidetes and Prevotella brevis were increased in the 40HG -fed goats as observed by using a qPCR platform. Additionally, methanogens and Methanomassiliicoccales were increased in high microalgae-fed goats, while Methanobrevibacter and Methanobacteriales were decreased. Fibrolytic bacteria were decreased in high microalgae-fed goats, while cellulolytic activity was increased. Ammonia was decreased in high grains-fed goats, while docosapentaenoic and docosahexaenoic acids showed a lower degradation rate in the rumen of high forage-fed goats. The alteration of the F:C ratio in goats supplemented with Schizochytrium spp. levels modified both ruminal microbiota and enzymatic activity. However, there was no significant consistency in the relations between them.

Assessing the Optimum Level of Supplementation with Camelina Seeds in Ewes' Diets to Improve Milk Quality

Camelina sativa seeds are rich in bioactive compounds such as polyunsaturated fatty acids (PUFA) and antioxidants, thus, their supplementation in ewes’ diets, may be an effective way to develop high nutritional dairy products. Therefore, the present study investigates the effect of the dietary inclusion of Camelina sativa seeds in ewes’ oxidative status and milk quality. Forty-eight dairy Chios ewes were divided into four homogenous groups and were fed individually. The concentrate of the control group (CON) had no inclusion of Camelina seeds, while the treatment groups (CSS6, CSS11, CSS16) were supplemented with 6%, 11%, and 16%, respectively. Including Camelina seeds in 6% and 11%, had no impact on milk performance, while in the CSS16, milk fat was significantly decreased compared to the CON. Supplementing Camelina seeds improved milk quality from a human health perspective by modifying the content of saturated fatty acid, the proportions of α-linolenic (C_{18:3 n-3}), and C_{18:2 cis-9, trans-11} (CLA), and the ω6/ω3 ratio. Furthermore, the activity of catalase (CAT) was significantly increased in the CSS11 and CSS16, and superoxide dismutase (SOD) activity also significantly upsurged in the CSS16. Still, the levels of malondialdehyde (MDA) were significantly increased in the CSS11 compared to the CON and CSS6, and in the CSS16 compared to the CSS6. In CSS16, protein carbonyls were significantly increased. Finally, in the CSS-fed ewes, milk oxidative stability was fortified, as suggested by the modifications in the activities of SOD, CAT, and glutathione peroxidase (GSH-Px), in the antioxidant capacity, and the oxidative stress biomarkers. Consequently, the incorporation of 6% Camelina seeds in the concentrates of ewes improves milk’s fatty acid profile and oxidative status. However, more research is required regarding the possible negative effects of the constant consumption of Camelina seeds by ewes.

Changes in the Rumen Bacteriome Structure and Enzymatic Activities of Goats in Response to Dietary Supplementation with Schizochytrium spp

With the aim to produce functional dairy products enriched with polyunsaturated fatty acids (PUFA) by using feed supplements, radical changes could occur in the rumen microbiome. This work investigated the alterations of the rumen bacteriome of goats fed with PUFA-rich marine microalgae Schizochytrium spp. For the trial, twenty-four goats were divided into four homogenous clusters (six goats/treatment) according to their fat-corrected (4%) milk yield, body weight, and age; they were individually fed with alfalfa hay and a concentrate (F/C = 50/50). The concentrate of the control group (CON) contained no microalgae, while those of the treated groups were supplemented daily with 20 (ALG20), 40 (ALG40), and 60 g (ALG60) of Schizochytrium spp./goat. Rumen fluid samples were collected using a stomach tube during the 20th and 40th days of the experiment. The microbiome analysis using a 16S rRNA sequencing platform revealed that Firmicutes were decreased in microalgae-fed goats, while Bacteroidetes showed a tendency to increase in the ALG40 group due to the enhancement of Prevotellaceae. Cellulolytic bacteria, namely Treponema bryantii, Ruminococcus gauvreauii, R. albus, and R. flavefaciens, were decreased in the ALG40 group, resulting in an overall decrease of cellulase activity. In contrast, the amylolytic potential was significantly enhanced due to an upsurge in Ruminobacter amylophilus, Succinivibrio dextrinosolvens, and Fretibacterium fastidiosum populations. In conclusion, supplementing goats’ diets with 20 g Schizochytrium spp. could be considered a sustainable and efficient nutritional strategy to modulate rumen microbiome towards the development of dairy products enriched with bioactive compounds, while higher levels induced substantial shifts in determinant microbes’ populations.

Changes in the Rumen Bacteriome Structure and Enzymatic Activities of Goats in Response to Dietary Supplementation with Schizochytrium spp

With the aim to produce functional dairy products enriched with polyunsaturated fatty acids (PUFA) by using feed supplements, radical changes could occur in the rumen microbiome. This work investigated the alterations of the rumen bacteriome of goats fed with PUFA-rich marine microalgae Schizochytrium spp. For the trial, twenty-four goats were divided into four homogenous clusters (six goats/treatment) according to their fat-corrected (4%) milk yield, body weight, and age; they were individually fed with alfalfa hay and a concentrate (F/C = 50/50). The concentrate of the control group (CON) contained no microalgae, while those of the treated groups were supplemented daily with 20 (ALG20), 40 (ALG40), and 60 g (ALG60) of Schizochytrium spp./goat. Rumen fluid samples were collected using a stomach tube during the 20th and 40th days of the experiment. The microbiome analysis using a 16S rRNA sequencing platform revealed that Firmicutes were decreased in microalgae-fed goats, while Bacteroidetes showed a tendency to increase in the ALG40 group due to the enhancement of Prevotellaceae. Cellulolytic bacteria, namely Treponema bryantii, Ruminococcus gauvreauii, R. albus, and R. flavefaciens, were decreased in the ALG40 group, resulting in an overall decrease of cellulase activity. In contrast, the amylolytic potential was significantly enhanced due to an upsurge in Ruminobacter amylophilus, Succinivibrio dextrinosolvens, and Fretibacterium fastidiosum populations. In conclusion, supplementing goats' diets with 20 g Schizochytrium spp. could be considered a sustainable and efficient nutritional strategy to modulate rumen microbiome towards the development of dairy products enriched with bioactive compounds, while higher levels induced substantial shifts in determinant microbes' populations.