A biofloc system avoids the adverse effects of diets with suboptimal protein levels on zootechnical performance, intestinal histomorphometry, and protein metabolism of Nile tilapia juvenile fed Spirulina biomass (Arthrospira platensis) as an alternative protein source

This study aimed to evaluate the effect of the biofloc technology (BFT) system and the replacement of fish meal with Spirulina biomass on productive performance, intestinal histomorphometry, plasma biochemistry, and oxidative stress of Nile tilapia juveniles (Oreochromis niloticus) fed suboptimal levels of protein. Two factors were evaluated: production systems (clear water × BFT) and replacement of fish meal with Spirulina (0, 33, 66 e 100%). The design was in a 2 × 4 randomized factorial scheme with four replications, and the fish were evaluated for 48 days. Four isoproteic (28% crude protein) diets were formulated with gross energy values close to 4300 kcal kg-1. Nile tilapia juveniles (0.23 ± 0.01 g) were distributed in 16 circular tanks (70 L) at seven fish/tank. The diets were formulated with protein levels approximately 20% below that required for the species and life stage. No interaction was observed between the factors evaluated (production systems × Spirulina inclusion). Rearing the fish in the BFT system avoided the adverse effects of diets with suboptimal protein levels on performance, intestinal histomorphometry, and protein metabolism. Lower values lower lipid peroxidation and higher antioxidant capacity were observed in fish reared in the BFT system, showing evidence of improvements in antioxidant responses and lower levels of physiological oxidative stress. Spirulina completely replaced fish meal in the diets of Nile tilapia juveniles without adverse effects on intestinal morphometry, protein metabolism, and antioxidant response. Replacing 66% of fish meal with Spirulina improved the productive performance, regardless of the rearing system.

The application of omics technologies for understanding tropical plants-based bioactive compounds in ruminants: a review

Finding out how diet impacts health and metabolism while concentrating on the functional qualities and bioactive components of food is the crucial scientific objective of nutritional research. The complex relationship between metabolism and nutrition could be investigated with cutting-edge "omics" and bioinformatics techniques. This review paper provides an overview of the use of omics technologies in nutritional research, with a particular emphasis on the new applications of transcriptomics, proteomics, metabolomics, and genomes in functional and biological activity research on ruminant livestock and products in the tropical regions. A wealth of knowledge has been uncovered regarding the regulation and use of numerous physiological and pathological processes by gene, mRNA, protein, and metabolite expressions under various physiological situations and guidelines. In particular, the components of meat and milk were assessed using omics research utilizing the various methods of transcriptomics, proteomics, metabolomics, and genomes. The goal of this review is to use omics technologies-which have been steadily gaining popularity as technological tools-to develop new nutritional, genetic, and leadership strategies to improve animal products and their quality control. We also present an overview of the new applications of omics technologies in cattle production and employ nutriomics and foodomics technologies to investigate the microbes in the rumen ecology. Thus, the application of state-of-the-art omics technology may aid in our understanding of how species and/or breeds adapt, and the sustainability of tropical animal production, in the long run, is becoming increasingly important as a means of mitigating the consequences of climate change.

EPC1/2 regulate hematopoietic stem and progenitor cell proliferation by modulating H3 acetylation and DLST

Enhancers of polycomb 1 (EPC1) and 2 (EPC2) are involved in multiple biological processes as components of histone acetyltransferases/deacetylase complexes and transcriptional cofactors, and their dysfunction was associated with developmental defects and diseases. However, it remains unknown how their dysfunction induces hematopoietic stem and progenitor cell (HSPC) defects. Here, we show that depletion of EPC1/2 significantly reduced the number of hematopoietic stem and progenitor cells (HSPCs) in the aorta-gonad mesonephros and caudal hematopoietic tissue regions by impairing HSPC proliferation, and consistently downregulated the expression of HSPC genes in K562 cells. This study demonstrates the functions of EPC1/2 in regulating histone H3 acetylation, and in regulating DLST (dihydrolipoamide S-succinyltransferase) via H3 acetylation and cooperating with transcription factors serum response factor and FOXR2 together, and in the subsequent HSPC emergence and proliferation. Our results demonstrate the essential roles of EPC1/2 in regulating H3 acetylation, and DLST as a linkage between EPC1 and EPC2 with mitochondria metabolism, in HSPC emergence and proliferation.

Dietary protein restriction regulates skeletal muscle fiber metabolic characteristics associated with the FGF21-ERK1/2 pathway

Under conditions of dietary amino acid balance, decreasing the dietary crude protein (CP) level in pigs has a beneficial effect on meat quality. To further elucidate the mechanism, we explored the alteration of muscle fiber characteristics and key regulators related to myogenesis in the skeletal muscle of pigs fed a protein restricted diet. Compared to pigs fed a normal protein diet, dietary protein restriction significantly increased the slow-twitch muscle fiber proportion in skeletal muscle, succinic dehydrogenase (SDH) activity, the concentrations of ascorbate, biotin, palmitoleic acid, and the ratio of s-adenosylhomocysteine (SAM) to s-adenosylhomocysteine (SAH), but the fast-twitch muscle fiber proportion, lactate dehydrogenase (LDH) activity, the concentrations of ATP, glucose-6-phosphate, SAM, and SAH in skeletal muscle, and the ratio of serum triiodothyronine (T3) to tetraiodothyronine (T4) were decreased. In conclusion, we demonstrated that dietary protein restriction induced skeletal muscle fiber remodeling association the regulation of FGF21-ERK1/2-mTORC1 signaling in weaned piglets.

Precision formulation, a new concept to improve dietary amino acid absorption based on the study of cationic amino acid transporters

Amino acid (AA) transporters (AAT) control AA cellular fluxes across membranes, contributing to maintain cellular homeostasis. In this study, we took advantage of rainbow trout metabolic feature, which highly relies on dietary AA, to explore the cellular and physiological consequences of unbalanced diets on AAT dysregulations with a particular focus on cationic AAs (CAA), frequently underrepresented in plant-based diets. Results evidenced that 24 different CAAT are expressed in various trout tissues, part of which being subjected to AA- and CAA-dependent regulations, with y+LAT2 exchanger being prone to the strongest dysregulations. Moreover, CAA were shown to control two major AA-dependent activation pathways (namely mTOR and GCN2) but at different strength according to the CAA considered. A new feed formulation strategy has been put forward to improve specifically the CAA supplemented absorption in fish together with their growth performance. Such "precision formulation" strategy reveals high potential for nutrition practices, especially in aquaculture.

Beyond probiotics: Exploring the potential of postbiotics and parabiotics in veterinary medicine

Postbiotics and parabiotics (PP) are emerging fields of study in animal nutrition, preventive veterinary medicine, and animal production. Postbiotics are bioactive compounds produced by beneficial microorganisms during the fermentation of a substrate, while parabiotics are inactivated beneficial microbial cells, either intact or broken. Unlike probiotics, which are live microorganisms, PP are produced from a fermentation process without live cells and show significant advantages in promoting animal health owing to their distinctive stability, safety, and functional diversity. PP have numerous beneficial effects on animal health, such as enhancing growth performance, improving the immune system and microbiota of the gastrointestinal tract, aiding ulcer healing, and preventing pathogenic microorganisms from colonizing in the skin. Moreover, PP have been identified as a potential alternative to traditional antibiotics in veterinary medicine due to their ability to improve animal health without the risk of antimicrobial resistance. This review comprehensively explores the current research and applications of PP in veterinary medicine. We aimed to thoroughly examine the mechanisms of action, benefits, and potential applications of PP in various species, emphasizing their use specifically in livestock and poultry. Additionally, we discuss the various routes of administration to animals, including feed, drinking water, and topical use. This review also presents in-depth information on the methodology behind the preparation of PP, outlining the criteria employed to select appropriate microorganisms, and highlighting the challenges commonly associated with PP utilization in veterinary medicine.

Using cattle hair to assess exposure to essential trace elements in volcanic soils

BACKGROUND

In areas where cattle graze outdoors, the environmental availability of trace elements is of utmost importance for an adequate intake. Cattle hair trace elements can be used as exposure biomarkers to assess animal intake and help ensure good nutrition and animal welfare. The aim of this study was to evaluate the environmental exposure to trace elements in cattle grazing outdoors in a volcanic region (São Miguel Island, Azores) and assess the corresponding bioaccumulation factors.

METHODS

Twenty-nine samples of pasture topsoil were collected in two areas of São Miguel with different geological characteristics: Picos fissure system (basaltic area) and Povoação volcano (trachytic area). Hair from fifty-four animals (calves and dairy cows) was collected in two grazing sites: Ponta Delgada (Picos fissure system) and Povoação (Povoação volcano). All samples were analysed by inductively coupled plasma mass spectrometry (ICP-MS) after digestion in aqua regia.

RESULTS

Basaltic soils of the Picos fissure system had significantly higher concentrations of most trace elements, except Mo, when compared with the trachytic soils of Povoação volcano. Hair of calves from Povoação showed higher concentrations of most essential trace elements, except Mg, Cu, and Zn, than hair from calves of Ponta Delgada (considered in this study as a control group since they are raised in a barn). On the other hand, hair from dairy cows grazing in Ponta Delgada showed higher concentrations of most essential trace elements, except Mg, As, and Mo, when compared with hair of cows grazing in Povoação.

CONCLUSIONS

Cattle hair trace elements are suitable biomarkers for the assessment of the environmental exposure to trace elements in volcanic soils. The results from dairy cows support the uneven distribution of essential trace elements (and their bioavailability) in the different soils of São Miguel, reinforcing the need to graze animals outdoors from an early age. Such practice (grazing cattle outdoors) provides another means of accessing essential trace elements that complemented with feed can reduce the natural depletion of these essential elements in the body due to reproductive phenomena and milk production.

Discrimination of different feed additives and poly-herbal formulations based on their untargeted phytochemical profiles

INTRODUCTION

Feed additives represents a valid tool in animal nutrition to improve animal performance and livestock productivity under a sustainable perspective; however, there is a paucity of information about their comprehensive metabolomic and bioactive profiles.

OBJECTIVE

In this study, we tested the ability of an untargeted metabolomics approach to discriminate nine commercial feed additives and unique blends of botanical extracts used in both ruminant and non-ruminant nutrition, according to their phytochemical profiles and different in vitro bioactive properties.

METHODS

An ultra-high-performance liquid chromatography coupled with Orbitrap mass spectrometry and multivariate statistics were combined to search for potential markers, in order to better discriminate the different commercial samples.

RESULTS

Several phytochemicals were identified, namely alkaloids, phenolics, organosulfurs, and terpenoids. The polyherbal formulation Zigbir was the best source of phytochemicals, accounting for a cumulative total content of phytochemicals equal to 3.03 mg Eq./g, being particularly abundant in terpenoids, stilbenes, phenolic acids, and small-molecular-weight phenolics. Multivariate statistics allowed to group the different products in 2 bioactive subclusters. The diterpenoid andrographolide recorded the highest abundance in Zigbir and Sangrovit. The most predictive biomarkers were: piperine, isoquercitrin, 6-methylthiohexyldesulfoglucosinolate, 6-methylumbelliferone, benzoic acid, (+)-(1R,2R)-1,2-diphenylethane-1,2-diol, and piperitenone. Flavonoids were highly correlated with both in vitro antioxidant and enzyme inhibition assays.

CONCLUSIONS

Our findings provide new insights into the comprehensive phytochemical composition of commercial feed additives and blend of botanical extracts used for both ruminant and non-ruminant nutrition. A great importance of polyphenols in relation to the biological activities was detected.

Adoption of on-farm feed safety practices among livestock farmers: Evidence from Saudi Arabia

Compliance with feed safety standards and practices on the farm promotes sustainable livestock production and can positively affect the environment and human health. This study aims to examine farmers' on-farm adoption of feed safety practices and determine the differences in adoption according to the socio-economic characteristics of farmers. An online survey was conducted to collect the study data. The study participants consisted of 442 livestock farmers in Riyadh region, Saudi Arabia. The study findings revealed that farmers highly adopted categories of feed purchasing (77.9 %) and feed mixing and distribution (75.05 %), whereas they were considered as a moderate level adoption regarding feed storing (70.9 %). The cluster analysis results showed two main patterns of adoption- "high adopters" and "moderate adopters"-based on the average level of adoption for 25 feed safety practices examined. The cluster of "high adopters" accounted for 59.9 % of the sample and had higher average adoption in all practices examined. The findings revealed that there are significant differences between the two segments of farmers, corresponding to gender, membership in livestock association, extension contact, raising sheep, and feeding system. This study proposes the regular monitoring of farms to ensure strict adherence to feed safety regulations, with the implementation of awareness and capacity development initiatives pertaining to feed safety concerns.

Can banana peel and sweet potato vines serve as efficient feed ingredients in diets for growing rabbits?

This study aimed to evaluate the use of banana peel (BP) and sweet potato vines (SPV) as a replacement for maize and alfalfa hay in diets for rabbits. Animal performance, economic analyses, meat composition, and color were evaluated for 49 days in a total 50 New Zealand White rabbits weaned at 35 days with an average body mass of ± 614 g. The animals were allotted, in a completely randomized design, having five dietary groups: control diet (0), without banana peels and sweet potato vines, or experimental diets, 25, 50, 75, and 100-with 25%, 50%, 75%, and 100% of banana peels and sweet potato vines in substitution to maize and alfalfa hay, respectively. The data were analyzed using ANOVA, while the means were compared by Tukey test (p < 0.05). The results indicate that daily feed intake, mass gain, and feed conversion were not statistically different from one another in the test groups compared to the control group treatment. In addition, the study shows no differences were observed in centesimal compositions and muscle color. The replacement of maize and alfalfa hay by the combination of BP and SPV resulted in reduction in feed costs, reaching 50% in the experimental diet with 100% of substitution the ingredients. It can be concluded, based on the results on animal performance, meat/color composition, and economic analyses, that BP and SPV may be used as a substitute for maize and alfalfa hay up to 100% in diets for growing rabbits.

Tuna sidestream valorization: a circular blue bioeconomy approach

Tuna is an economically significant seafood, harvested throughout the world, and is heavily traded due to its high nutritional quality and consumer acceptance. Tuna meat is rich in essential nutrients such as amino acids, polyunsaturated fatty acids (PUFA), and trace minerals. The huge volume of solid and liquid sidestreams generated during the processing stages of tuna is creating environmental and socioeconomic challenges in coastal areas. Different products such as fish meal, protein hydrolysates, collagen, enzymes, oil, and bone powder can be produced from tuna sidestreams. Using different nutrient recovery technologies like enzymatic hydrolysis, chemical processing, and green technologies, various categories of product value chains can be created in line with the conventional processing industry. This review attempts to provide a route map for the tuna industry for achieving the circular blue-bioeconomic objectives and reorient the irregular utilization pattern into a sustainable and inclusive path.

Systematic review of the relationship between rumen acidosis and laminitis in cattle

Laminitis is usually considered a consequence of digestive disorders that reduce ruminal pH. However, it is still not clear the direct relation between low ruminal pH provoked by excessive fast-digesting carbohydrate ingestion and laminitis, considering indicators, signs, and diagnosis aspects. This study aimed to clarify the association between different clinical presentations of laminitis with ruminal acidosis provoked by diet using the systematic review methodology. Three electronic databases were used: ISI Web of Science, PubMed, and Scopus. A total of 339 manuscripts were identified and only 16 were included. Manuscripts were published between 2000 and 2021 in 11 different peer-reviewed journals. Fifteen studies confirmed the occurrence of ruminal acidosis. The main indicators used were ruminal pH and clinical signs, such as anorexia, depression, discomfort and diarrhea. Two of the studies that administered oligofructose to induce acidosis and acute laminitis did not observe clinical signs of laminitis, using lameness score or hooves' sensitivity as an indicator. Various diagnostic methods were used to describe laminitis, like thermography, hoof biopsy, sensitivity test, and visual inspection. Although the variety of laminitis indicators used in the included studies, we evidence the existence of an association between diet (high level of fast-digesting carbohydrates), ruminal acidosis, and acute laminitis, mostly in the short-term acidosis' induction protocols, but the mechanism of action is still not clear.

Dataset of feed bunk score images of cattle feedlot

Bunk management is an important technique to minimize the variations in consumption in feedlot cattle and can be performed according to the South Dakota State University classification system. The use of information and communication technology (ICT) can help, in an objective way, in the interpretation of these measurements. We created a dataset with the objective to develop an automatic classification method of feed bunk score. In May, September and October on the 2021 and September on the 2022 we captured 1511 images in the morning on the farms, in natural lighting conditions with different angles and backgrounds and at a height of about 1.5 m from the bunk. After acquisition data, each image was classified according to its score classification. Additionally, we resized the images to 500 × 500 pixels, generated annotations files, and organized the dataset in folders. The images in this dataset can be used to train and validate a machine learning model to classify feed bunk images. This model can be used to develop an application to support bunk management.

Assessment of cecal microbiota modulation from piglet dietary supplementation with copper

BACKGROUND

Swine production expanded in the last decades. Efforts have been made to improve meat production and to understand its relationship to pig gut microbiota. Copper (Cu) is a usual supplement to growth performance in animal production. Here, two performance studies were conducted to investigate the effects of three different sources of Cu on the microbiota of piglets. A total of 256 weaned piglets were randomly allocated into 4 treatments (10 replicates per treatment of 4 piglets per pen in Trial 1 and 8 replicates of 3 piglets per pen in Trial 2). Treatments included a control group (fed 10 mg/kg of Cu from CuSO₄), a group fed at 160 mg/kg of Copper (II) sulfate (CuSO₄) or tri-basic copper chloride (TBCC), and a group fed with Cu methionine hydroxy analogue chelated (Cu-MHAC) at 150, 80, and 50 mg/kg in Phases 1 (24-35 d), 2 (36-49 d), and 3 (50-70 d), respectively. At 70 d, the cecum luminal contents from one pig per pen were collected and polled for 16 S rRNA sequencing (V3/V4 regions). Parameters were analyzed in a completely randomized block design, in which each experiment was considered as a block.

RESULTS

A total of 1337 Operational Taxonomic Units (OTUs) were identified. Dominance and Simpson ecological metrics were statistically different between control and treated groups (P < 0.10) showing that different Cu sources altered the gut microbiota composition with the proliferation of some bacteria that improve gut health. A high abundance of Prevotella was observed in all treatments while other genera were enriched and differentially modulated, according to the Cu source and dosage. The supplementation with Cu-MHAC can modify a group of bacteria involved in feed efficiency (FE) and short chain fatty acids (SCFA) production (Clostridium XIVa, Desulfovibrio, and Megasphera). These bacteria are also important players in the activation of ghrelin and growth hormones that were previously reported to correlate with Cu-MHAC supplementation.

CONCLUSIONS

These results indicated that some genera seem to be directly affected by the Cu source offered to the animals. TBCC and Cu-MHAC (even in low doses) can promote healthy modifications in the gut bacterial composition, being a promising source of supplementation for piglets.

Sugarcane yeast with urea in replace of soybean meal in the diet of Murrah buffaloes does not cause metabolic, endocrine, and mineral disorders

The aim of this study was to evaluate the effect of the replacement of soybean meal by increasing levels of sugarcane yeast and urea on the energy, enzymatic, protein, mineral, and hormonal profiles of buffalo heifers. Twenty Murrah heifers with an average body weight of 168 ± 2.0 kg and 1 year old were used in a completely randomized design. The treatments consisted of the replacement of soybean meal by increasing levels of sugarcane yeast and urea (0, 33, 67, and 100% dry matter). The animals were weighed at the beginning and end of the experimental period, and blood was collected on the final day. The replacement of soybean meal with sugarcane yeast influenced the performance and metabolic dynamics, with total weight gain (P = 0.005) and average daily gain (P = 0.015), presenting, for both variables, a quadratic effect. Considering the biochemical profile, there was an influence on the serum concentration of triglycerides (P = 0.055), the serum activities of aspartate aminotransferase, gamma-glutamyl transferase, and alkaline phosphatase (P < 0.05), in addition to the serum concentration of phosphorus (P = 0.007) and potassium (P = 0.053), which showed positive linear effects. The hormonal profile was not influenced by diets (P > 0.05). The elements copper, iron, and zinc were able to be quantified at all levels of sugarcane yeast and urea in the diets offered. The use of sugarcane yeast with urea promotes adequate metabolic response of buffalo heifers and can replace up to 100% of soybean meal in the concentrate.

High-throughput amplicon sequencing datasets of the metacommunity DNA of the gut microbiota of Zebrafish Danio rerio fed diets with differential quantities of protein and fat contents

In this paper, we present high-throughput amplicon sequence (HTS) datasets of the gut microbiota of male and female Zebrafish Danio rerio fed diets consisting of sub-optimal and above-optimal quantities of proteins and fats. The HTS datasets were generated using an Illumina MiSeq targeting the V4 hypervariable segment of the 16S rRNA gene. The raw sequence reads were quality checked, demultiplexed into FASTQ files, denoised using DADA2 (q2-dada2 denoise-paired), and subsampled. Taxonomic ids were then assigned to amplicon sequence variants (ASVs) against the silva-138-99-nb-classifier for taxonomic output using the Quantitative Insights Into Microbial Ecology (QIIME2 v2021.4). The resultant taxa list was generated at the phylum level to confirm the applicability of the HTS dataset using the "qiime taxa collapse" command. These HTS datasets of the metagenome can be accessed through the BioSample Submission Portal (https://www.ncbi.nlm.nih.gov/bioproject/) under the BioProject IDs PRJNA772302 and PRJNA772305.

Canada jays (Perisoreus canadensis) balance protein and energy targets simultaneously in both consumed and cached food

Food scarce periods pose serious physiological challenges for birds, especially in energetically demanding conditions. For species in the northern hemisphere, a decrease in available resources during winter adds further physiological stress to the energetic demands of life at low temperatures. Some species cache food to provide a reliable energy and nutrient resource during scarcity. Canada Jays are a year-round food-caching resident of the North American boreal forest. Canada Jays also rear their young prior to spring green up, making food caching not only essential for adult winter survival, but also potentially important for meeting the requirements of growing offspring in late winter and early spring. We examined the diet choices of Canada Jays immediately prior to winter, and the macronutrient composition of the foods Canada Jay consumed and cached at this time. We found that Canada Jays cache the same relative amounts of macronutrients as they consume but did not vary macronutrients seasonally. The similarities in the macronutrient proportions cached and consumed suggest a consistent nutrient intake pattern, and that Canada Jays are foraging to simultaneously meet similar minimum energy and minimum protein targets for both the present and future. These simultaneous targets constrain the caching decisions of jays when presented with dietary choices.

Comfrey (Symphytum spp.) as a feed supplement in pig nutrition contributes to regional resource cycles

In smallholder agriculture, the fast-growing and perennial accumulator plant comfrey (Symphytum spp.) was used to supply pigs with protein and minerals. Comfrey leaves show similar values in dry matter as soybean or blue lupine in crude protein content, but much higher levels of calcium and phosphorus. However, in terms of increased efficiency in animal husbandry, comfrey has been displaced by mainly soybean and cereals. Due to its profile of macro- and micronutrients the use of comfrey could have the potential to re-establish local resource cycles and help remediate over-fertilized soils. The aim of the study was to evaluate whether a modern pig breed accepts a continuous feed supplement of dried comfrey leaves. After an initial adaptation period post-weaning, German Landrace piglets were subjected to either a standard control diet or a diet supplemented with 15% dried comfrey leaves for 4 weeks. Body weight was reduced in comfrey-supplemented piglets compared to controls, which might be attributed to reduced palatability in the experimental setting. Nevertheless, comfrey-supplemented piglets exhibited adequate bone mineralization and intestinal integrity. The microbiome profile in feces and digesta revealed higher diversity in comfrey-supplemented piglets compared to controls, with pronounced effects on the abundances of Treponema and Prevotella. This may be due to described bio-positive components of the comfrey plant, as data suggest that the use of comfrey leaves may promote intestinal health. Digestive tract phosphorus levels were reduced in piglets receiving comfrey supplementation, which may ultimately affect phosphorus levels in manure. Results indicate that comfrey leaves could serve as a feed component in integrated agricultural systems to establish regional nutrient cycles. The trial provides a basis for further work on comfrey as a regionally grown protein source and effective replacement for rock mineral supplements.

Properties of corn-expressed carbohydrase AC1 in swine diets and its effects on apparent ileal digestibility, performance, hematology, and serum chemistry

Carbohydrases are often incorporated into livestock feed as digestive aids to improve animal performance. AC1 is a thermostable carbohydrase with β-1,4-glucanase, endo-cellulase, and cellobiohydrolase activity. AC1 has been expressed in corn, where it accumulates in the grain for easy inclusion in animal diets. Incorporating the enzyme in high-fiber diets (corn-soy supplemented with distiller's dry grains with solubles) that were fed to 5-week-old pigs led to a trend of decreasing viscosity of the digesta as the dose of the enzyme increased (P = 0.092). AC1 also tended to increase the apparent ileal digestibility (AID) of neutral detergent fiber (P = 0.076). When fed diets containing 2126 U/kg AC1, pigs experienced no adverse effects in terms of performance metrics (body weights, average daily gain, average daily feed intake and gain-to-feed ratio), hematology, blood chemistry or general health when compared to pigs fed a control diet that lacked AC1.

Review: Managing sheep and goats for sustainable high yield production

This review discusses the most relevant aspects of nutritional, reproductive and health management, the three pillars of flock efficiency, production and sustainability regarding the intensification of production in sheep and goats. In small ruminants, reproductive management is dependent on seasonality, which in turn depends on breed and latitude. Nutrition represents the major cost for flocks and greatly affects their health, the quality of their products and their environmental impact. High-yielding sheep and goats have very high requirements and dietary intake, requiring nutrient-dense diets and sophisticated nutritional management that should always consider the strong interrelationships among nutrition, immunity, health, reproduction, housing and farm management. The reproductive pattern is to a great extent assisted by out-of-season breeding, facilitating genetic improvement schemes, and more recently by advanced reproductive technologies. Heath management aims to control or eradicate economic and zoonotic diseases, ensuring animal health and welfare, food safety and low ecosystem and environmental impacts in relation to chemical residues and pathogen circulation. In highly producing systems, nutrition, genetic and hazard factors assume a complex interrelationship. Genomic and management improvement research and technological innovation are the keys to sustain sheep and goat production in the future.

Organoids: a promising new in vitro platform in livestock and veterinary research

Organoids are self-organizing, self-renewing three-dimensional cellular structures that resemble organs in structure and function. They can be derived from adult stem cells, embryonic stem cells, or induced pluripotent stem cells. They contain most of the relevant cell types with a topology and cell-to-cell interactions resembling that of the in vivo tissue. The widespread and increasing adoption of organoid-based technologies in human biomedical research is testament to their enormous potential in basic, translational- and applied-research. In a similar fashion there appear to be ample possibilities for research applications of organoids from livestock and companion animals. Furthermore, organoids as in vitro models offer a great possibility to reduce the use of experimental animals. Here, we provide an overview of studies on organoids in livestock and companion animal species, with focus on the methods developed for organoids from a variety of tissues/organs from various animal species and on the applications in veterinary research. Current limitations, and ongoing research to address these limitations, are discussed. Further, we elaborate on a number of fields of research in animal nutrition, host-microbe interactions, animal breeding and genomics, and animal biotechnology, in which organoids may have great potential as an in vitro research tool.

Effects of dietary conjugated linoleic acid on metabolic status, BW and expression of genes related to lipid metabolism in adipose tissue of dairy cows during peripartum

Conjugated linoleic acid (CLA) dietary supplementation reduces milk fat content and yield, but its effects on lipid metabolism and energy status remain controversial. The objective of this study was to investigate the effects of dietary CLA on adipose tissue (AT) mRNA abundance of genes related to lipid metabolism, plasma indicators of metabolic status, body condition score (BCS) and BW changes in dairy cows. Sixteen multiparous Holstein cows (3.2 ± 1.4 lactations, 615 ± 15 kg BW) were randomly assigned to treatments: 1) CLA; rumen-protected CLA (75 g/d) or 2) Control; equivalent amount of rumen inert fatty acid (FA) as the previous diet (78 g/d), from -20.2 ± 3.2 (mean ± SEM) to 21d relative to calving (d 0). Subcutaneous AT was biopsied from the tail-head region at d 21 to determine the mRNA abundance of genes related to lipid metabolism. Blood samples were collected at -20.2 ± 3.2, 0, 7, 14 and 21d relative to calving to determine plasma non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHBA), insulin and glucose. Conjugated linoleic acid decreased milk fat yield and milk fat content by 15 and 16%, respectively. Cows fed CLA had lower plasma NEFA and BHBA and greater glucose and insulin concentrations (P < 0.05). Mean BCS at 21d postpartum was greater (P < 0.01; 2.89 vs 2.25), and BCS loss from the day of enrollment to 21d postpartum was reduced (P < 0.01; -0.13 vs -0.64) in the CLA group. The expression of acylcoenzyme A oxidase, carnitine palmitoyltransferase 1A, hormone-sensitive lipase, β2 adrenergic receptor and acetyl-CoA carboxylase was downregulated by CLA supplementation, whereas the expression of sterol regulatory element binding protein, lipoprotein lipase and peroxisome proliferator-activated receptor gamma was upregulated (P < 0.01). In summary, CLA-supplemented cows showed signs of better metabolic status and less severe fat mobilization. Moreover, CLA increased mRNA abundance of genes related to lipogenesis and decreased mRNA abundance of genes related to FA oxidation and lipolysis in the AT of dairy cows during early lactation.

Effect of different dietary levels of corn naturally contaminated with DON and its derivates 3+15 Ac-DON and DON-3-glucoside on the performance of broilers

In the field of mycotoxin research, there is an increasing requirement to understand the effect of these toxins at realistic contamination levels, and as mixtures, on animal health and performance. Although there are recommendations of maximum levels of some mycotoxins in feed, it is known from practice that concentrations below the maximum recommended levels already negatively affect livestock production. In the present study, we exposed broilers to three different levels of naturally contaminated diets containing deoxynivalenol (DON) and its derivates 3 + 15 Acetyl-DON (3 + 15 Ac-DON) and DON-3-glucoside (DON-3-G) to evaluate their effect on birds performance. 630 day-old Ross 308 broilers were housed in 30 pens (21 birds per pen) and fed diets containing increasing levels of DON (Low: 1,650–1,890 μg/kg; Moderate: 2,500–2,880 μg/kg DON; and High: 3,220–3,900 μg/kg), 3 + 15 Acetyl-DON (Low: 25.6–39.4 μg/kg; Moderate: 42.3–49.1 μg/kg; and High: 58.4–71.1 μg/kg), and DON-3-G (Low: 356–362 μg/kg; Moderate: 405–637 μg/kg; and High: 625–787 μg/kg). Each diet had 10 replicate pens. During the grower period (D13-28) broilers fed diets containing moderate and high contamination levels presented a significantly increased feed intake but accompanied by significant impairment in FCR when the broilers were fed the highest contamination level. Based on this, it can be concluded that broiler production is affected when feed is contaminated with a mixture of DON and its derivates, even at levels below the EU maximum recommendation of 5,000 μg/kg. Furthermore, extra attention should be given to multi-mycotoxins contamination in diets for broilers up to 28 days old.

Lantibiotic Nisin Applied in Broiler Rabbits and Its Effect on the Growth Performance and Carcass Quality

Nisin is a bacteriocin marketed as Nisaplin. The aim of this study was to follow the effect of commercial lantibiotic nisin on the growth performance and carcass quality of broiler rabbits. The increase of average daily gain (by 9.4%) was recorded in the nisin group. The treatment did not have a negative influence on the pH, colour, water-holding capacity, protein and fat contents or energetic value of the rabbit carcass. Inferring from the higher average daily gain and the higher protein and lower fat content, we conclude that the diet supplementation with nisin may enhance the quality of rabbit meat.

Socio-economic determinants and impact of adopting climate-smart Brachiaria grass among dairy farmers in Eastern and Western regions of Kenya

The sustainability of the livestock sector in sub-Saharan Africa is negatively affected by limited access to high-quality fodder in adequate quantities. The effects of climate change further exacerbate feed availability. Therefore, there is a need to develop feasible cost-effective strategies for improving the year-round feed supply. Improved planted forages such as Brachiaria grass have been recommended as one of the strategies of alleviating feed scarcity, especially in drier agro-ecological zones. This study analyses the socio-economic determinants of adoption and the impact of adopting Brachiaria grass for feed sufficiency and increased milk production. Propensity Score Matching (PSM) method was used to assess the determinants and impact of the adoption of Brachiaria grass. Empirical results indicate that the adoption of Brachiaria grass led to a significant increase in milk production by 27.6% and feed sufficiency by 31.6%. The positive impact of Brachiaria grass is consistent with the role of agricultural technologies in improving the productivity, income, and welfare of smallholder farmers. The adoption of Brachiaria grass is influenced by age of farmer, tropical livestock unit (TLU), type of animal breed, perceived benefits of the technology, access to extension, and farmer group membership. The study recommends holistic policy approaches that promote the widespread adoption of Brachiaria grass. There is also a need for an effective information dissemination pathway for Brachiaria grass.

Effects of supplementation of green tea extract on the milk performance of peripartal dairy cows and the expression of stress response genes in the liver

Background

We hypothesised that supplementation of green tea extract (GTE) in dairy cows during the transition period can attenuate proinflammatory conditions and prevent endoplasmic reticulum (ER) stress in the liver of these cows. Thirty Holstein cows with an average parity of 3.06 (± 1.31, SD) were divided into a control group and a group that received a daily amount of 10 g of GTE from d 7 before the calving day and a daily amount of 20 g of GTE from the day of calving until d 7 of lactation.

Results

Cows supplemented with GTE did not show differences in energy intake or milk yield in weeks 2–7 of lactation. However, these cows had a lower milk fat concentration and a lower energy corrected milk yield than the control cows and showed a trend of improved energy balance. The relative mRNA concentrations of proinflammatory genes, genes involved in the acute phase reaction and antioxidant genes in the liver in weeks 1, 4 and 7 of lactation were not different between the two groups of cows. The concentrations of α-tocopherol and the Trolox equivalent antioxidant capacity in plasma were not different between the two groups. However, the group supplemented with GTE showed significant reductions of some genes of the unfolded protein response (UPR) in week 1 and a trend of lower liver triacylglycerol (TAG) concentrations in the liver compared to the control group.

Conclusions

This study shows that supplementation of GTE in dairy cows lowers the fat concentration in the milk but overall has no effect on the expression of inflammatory genes and the antioxidative status in dairy cows during early lactation. The finding of reduced mRNA levels of genes involved in the UPR at week 1, however, supports other results showing that supplementation of polyphenols could prevent the development of ER stress in the liver of cows during early lactation. The finding of a tendency towards a reduced TAG concentration in the liver of cows supplemented with GTE might be due to an improved energy balance in these cows.

Comprehensive evaluation of the metabolic effects of insect meal from Tenebrio molitor L. in growing pigs by transcriptomics, metabolomics and lipidomics

Background

The hypothesis was tested that insect meal (IM) as protein source influences intermediary metabolism of growing pigs. To test this, 30 male, 5-week-old crossbred pigs were randomly assigned to 3 groups of 10 pigs each with similar body weights (BW) and fed isonitrogenous diets either without (CON) or with 5% IM (IM5) or 10% IM (IM10) from Tenebrio molitor L. for 4 weeks and key metabolic tissues (liver, muscle, plasma) were analyzed using omics-techniques.

Results

 Most performance parameters did not differ across the groups, whereas ileal digestibilities of most amino acids were 6.7 to 15.6%-units lower in IM10 than in CON (P < 0.05). Transcriptomics of liver and skeletal muscle revealed a total of 166 and 198, respectively, transcripts differentially expressed between IM10 and CON (P < 0.05). Plasma metabolomics revealed higher concentrations of alanine, citrulline, glutamate, proline, serine, tyrosine and valine and a lower concentration of asparagine in IM10 than in CON (P < 0.05). Only one out of fourteen quantifiable amino acid metabolites, namely methionine sulfoxide (MetS), in plasma was elevated by 45% and 71% in IM5 and IM10, respectively, compared to CON (P < 0.05). Plasma concentrations of both, major carnitine/acylcarnitine species and bile acids were not different across groups. Lipidomics of liver and plasma demonstrated no differences in the concentrations of triacylglycerols, cholesterol and the main phospholipids, lysophospholipids and sphingolipids between groups. The percentages of all individual phosphatidylcholine (PC) and phosphatidylethanolamine (PE) species in the liver showed no differences between groups, except those with 6 double bonds (PC 38:6, PC 40:6, PE 38:6, PE 40:6), which were markedly lower in IM10 than in CON (P < 0.05). In line with this, the percentage of C22:6n-3 in hepatic total lipids was lower in IM10 than in the other groups (P < 0.05).

Conclusions

Comprehensive analyzes of the transcriptome, lipidome and metabolome of key metabolic tissues indicate that partial or complete replacement of a conventional protein source by IM in the diet has only a weak impact on the intermediary metabolism of growing pigs. Thus, it is concluded that IM from Tenebrio molitor L. can be used as a dietary source of protein in pigs without causing adverse effects on metabolism.

A novel thermal hydrolysis process for extraction of keratin from hog hair for commercial applications

We have developed a novel thermal hydrolysis process (THP) to extract and hydrolyze keratin from keratinous animal body wastes without using any chemicals. Our process consists of two heating steps: one is to swell and denature the keratin protein network in the intermediate filaments, while the other is to cleavage the disulfide bonds that connect the tight keratinous fibrils together. Using hog hair as an example, the two-step process achieved a nearly 70% keratin recovery yield, with respect to the original keratin in the hog hair, which is comparable to one of the best recovery yields by conventional chemical processes. The extracted keratin hydrolysate by THP was filtered by the shear wave-induced membrane ultrafiltation for characterization. The molecular weight (MW) analysis using SDS-PAGE and MALDI-TOF mass spectroscopy has demonstrated that our keratin hydrolysis obtained by our two-step THP has a wide range of MW distribution, similar to those already in the hair-care product market. The amino acid composition analysis has shown that our keratin hydrolysate by THP had twice as much essential amino acids as soybean meals on a dry mattter basis. As to the cysteine residue content, we have shown that it can be controlled by adjusting the 2nd heating temperature.

Calf demand provision by mammary gland secretion during the first decade of post-natal development

The article highlights the experimental results on calf demand provision by mammary gland secretion during the first days of post-natal development. Changes in mammary gland secretion content during the transition process from colostrum to natural milk were showed. Lactoferrin level changes were demonstrated. Population-based composition of colostrum somatic cells was determined. A hypothesis concerning apoptosis role of the somatic cells and neutrophils’ burst was presented. The present study highlights calf provision with mammary gland secretion during the first 10 days of the postnatal development.

Safety and efficacy evaluation of a novel dietary muramidase for swine

The safety of a novel microbial muramidase (Muramidase 007) as a feed additive for swine was evaluated in a target animal safety study (Experiment 1). Forty weanling pigs were allotted to 4 dietary treatments: T1 control group, and 3 groups receiving Muramidase 007 in increasing doses: T2 65,000 (1X), T3 325,000 (5X) and T4 650,000 (10X) LSU(F)/kg feed. The efficacy of Muramidase 007 on growth performance was evaluated in a feeding experiment (Experiment 2). A total of 288 piglets were allotted to two groups: T1 control group and T2 receiving Muramidase 007 at 50,000 (LSU(F)/kg feed. In Experiment 1, no growth depression of pigs was observed. No adverse effects of Muramidase 007 were observed for any of the hematology and serum chemistry parameters measured or on pig health status. Post-mortem evaluation showed no adverse effects due to Muramidase 007 supplementation in the gross pathology or in the histological examination. In Experiment 2, Muramidase 007 significantly increased overall (d 0-42) average daily gain (ADG) and tended to improve overall average daily feed intake (ADFI) and day 42 body weight of nursery pigs and had no effect on feed conversion ratio (FCR). Overall, results of these studies show that there were no adverse effects of Muramidase 007 compared to the control group.

Glucose and glycogen levels in piglets that differ in birth weight and vitality

In the pig, intrauterine crowding can greatly affect postnatal characteristics, among which birth weight and locomotion. In a previous study, we discovered that piglets with a low birth weight/low vitality (L piglets) have a reduced motor performance compared to piglets with a normal birth weight/normal vitality (N piglets). A possible explanation is that L piglets lack the energy to increase their motor performance to the level of that of N piglets. Blood glucose levels (GLU) and glycogen concentrations in skeletal muscle of the front (GLY_FRONT) and hind leg (GLY_HIND) and the liver (GLY_LIVER) at birth and during the first 96 h postpartum were compared between L and N piglets. GLU at birth was the same for both groups. After birth, GLU immediately increased in N piglets, whereas it only increased after 8 h in L piglets. L piglets showed a lower GLY_HIND at birth and did not use this glycogen during the first 8 h postpartum, while N piglets showed a gradual depletion. GLY_LIVER at birth was 50% lower for L piglets and was unused during the studied period while N piglets consumed half of their GLY_LIVER during the first 8 h. Based on these results, it is possible that lower glycogen concentrations at birth, the delayed increase in GLU and the lower use of glycogen during the first 8 h after birth negatively affect motor performance in L piglets. However, based on this study, it is unclear whether the low mobilization of glycogen by L piglets is a consequence, rather than a cause of their lower motor performance.

Performance, meat characteristics and economic viability of rabbits fed diets containing banana peel

In developing countries, agricultural areas are used to grow ingredients for rabbits' nutrition instead of food for the human population. In this context, in places where people starve, it is unreasonable to use ingredients, such as maize, in rabbits' diets. This research aimed to evaluate performance, meat composition and coloration, and economic viability in rabbits fed with diets containing banana peel (BP) in substitution to maize. Forty-five White New Zealand rabbits were used; they were weaned at 35 days old and divided into five treatments in a completely randomized design. The animals were fed with some of the following diets: control diet (0BP)-without banana peel; experimental diets: 25BP, 50BP, 75BP and 100BP-with 25%, 50%, 75% and 100% of banana peel in substitution to maize, respectively. Means were compared through analysis of variance, followed by Tukey test (0.05). Results indicate there were no differences in performance and meat parameters. Banana peel inclusion resulted in lower costs. Therefore, banana peel can replace maize up to 100% in diets for rabbits with no loss in performance and meat composition, representing a promising alternative in rabbits' nutrition.

Soybean grain is a suitable replacement with soybean meal in multiple supplements for Nellore heifers grazing tropical pastures

The research aimed to evaluate the effect of replacing soybean meal with soybean grain on the nutritional parameters and productivity of heifers grazing on Urochloa decumbens in the rainy-dry transition period. Forty crossbred heifers with the initial age and weight of 18 months and 292 ± 6.1 kg, respectively, were used. The experimental design was a completely randomized design, with five treatments and eight replications. The evaluated treatments were as follows: SM0.5-supply of 0.5 kg/animal/day of soybean meal supplement; SG0.5-supply of 0.5 kg/animal/day of soybean grain supplement; SM1.0-supply of 1.0 kg/animal/day of soybean meal supplement; SG1.0-supply of 1.0 kg/animal/day of soybean grain supplement; MM-only mineral mix ad libitum. The supplement was isoprotein with 350 g of crude protein/kg of dry matter. Supplementation improved the performance of the heifers and this fact can be verified by the higher average daily gain (ADG) and final BW (fBW) of the supplemented animals (P < 0.10). The two supplemented treatments with 1 kg/day demonstrated similar performance (P > 0.10), the same happens for the two treatments receiving 0.5 kg/day (P > 0.10). However, animals receiving 1 kg/day of supplementation had an ADG and final BW higher than animals receiving 0.5 kg/day (P < 0.10). Supplementation (P < 0.10) affected the intake of dry matter (DM), organic matter, crude protein, ether extract, non-fiber carbohydrates, total digestible nutrients, and neutral detergent fiber corrected for ash and protein (apNDF). Supplementation improved DM digestibility and all constituents of the diet (P < 0.10), except for apNDF (P > 0.10). In summary, it is concluded that multiple supplementations improve the performance of grazing heifers in the rainy-dry transition period and the total replacement of soybean meal by soybean grain does not alter the performance of the animals.

Nutritional planning for Nellore heifers post-weaning to conception at 15 months of age: performance and nutritional, metabolic, and reproductive responses

The objective of this study was to evaluate the effects of strategic supplementation in the dry period and dry/rainy transition period on the performance and nutritional, metabolic, and reproductive responses of Nellore heifers grazing Urochloa decumbens. Forty-eight Nellore heifers with age and body weight (BW) of eight months and 235 ± 3.3 kg, respectively, were used. The experimental design was a completely randomized design, with four treatments, all with 12 replications. The evaluated strategies were as follows: low supplementation (LOHI; 0.2% of BW/heifer/day) in the first 90 days and high supplementation (0.6% of BW/heifer/day) in the 90 days thereafter; average supplementation (AVER) with 0.4% of BW/heifer/day for 180 days; high supplementation (HILO; 0.6% of BW/heifer/day) in the first 90 days and low supplementation (0.2% of BW/heifer/day) in the 90 days thereafter; only mineral mix (MM) ad libitum during the 180 days. Data were evaluated using orthogonal contrasts. Supplementation improved the performance of the animals during of dry period (P < 0.05) and dry/rainy transition period (P < 0.05). Supplemented animals had higher longissimus muscle area (LMA) and subcutaneous fat thickness (SFT) at the end of the experiment (P < 0.05). Multiple supplementation increased intake of dry matter (DM), organic matter (OM), and crude protein (CP) in kg/day throughout the experiment. The supplementation increased the digestibility of DM, OM, CP, apNDF, and TDN (P < 0.05). Serum urea nitrogen (SUN), glucose (GLUC), insulin (INS), and progesterone (PROG) were higher in supplemented heifers (P < 0.05). Supplementation reduced the concentrations of non-esterified fatty acids (NEFA) (P < 0.05) and increased conception rate (P < 0.05). In summary, the supplementation strategies adopted in this study improve the performance, metabolic status, and carcass traits of heifers under grazing, allowing an improvement in the conception rate of 15-month-old Nellore heifers.

Antioxidant status of rats' blood and liver affected by sodium selenite and selenium nanoparticles

Background

Selenium is an essential element; however, at higher doses, it can be toxic. Therefore, alternative nanotechnological solutions are required to overcome toxicological issues, rather than conventional alternatives. Nanoparticles show new and promising properties that may be able to suppress toxicity while maintaining the positive effects of selenium on an organism. The aim of the experiment was to determine the influence of sodium selenite and selenium nanoparticles (SeNPs) on the antioxidant status of rats.

Methods

The males of the outbreed rat strain Wistar albino were selected as a model organism. Animals were fed different forms of selenium. The control group was given a mixture without selenium addition, whereas other groups were fed a mixture containing sodium selenite, Se-49, and Se-100 SeNPs respectively. The duration of the trial was 30 days.

Results

Analysis of blood and liver was performed where the concentration of reduced (GSH) and oxidised (GSSG) glutathione, and total selenium content were measured. In the liver, a significant reduction in GSSG was found for all experiment groups. Blood samples showed a significant reduction in GSH and an increase in GSSG.

Discussion

These results show that SeNPs may be an alternative to dietary selenium for animal organisms.

Allergenic potential of novel proteins - What can we learn from animal production?

Currently, risk assessment of the allergenic potential of novel proteins relies heavily on evaluating protein digestibility under normal conditions based on the theory that allergens are more resistant to gastrointestinal digestion than non-allergens. There is also proposed guidance for expanded in vitro digestibility assay conditions to include vulnerable sub-populations. One of the underlying rationales for the expanded guidance is that current in vitro assays do not accurately replicate the range of physiological conditions. Animal scientists have long sought to predict protein and amino acid digestibility for precision nutrition. Monogastric production animals, especially swine, have gastrointestinal systems similar to humans, and evaluating potential allergen digestibility in this context may be beneficial. Currently, there is no compelling evidence that the mechanisms sometimes postulated to be associated with allergenic sensitization, e.g. antacid modification of stomach pH, are valid among production animals. Furthermore, examples are provided where non-biologically representative assays are better at predicting protein and amino acid digestibility compared with those designed to mimic in vivo conditions. Greater emphasis should be made to align in vitro assessments with in vivo data.

Comparison of milk fatty acid profiles measured on Kouri cows near Lake Chad and on dairy cattle as reported by meta-analytical data

Kouri (Bos taurus) is a breed aboriginal from Lake Chad and threatened with extinction. This study aimed to compare milk fatty acid profiles measured on Kouri cows and on high-yielding dairy cattle in Europe and elsewhere as reported by meta-analytical data (22 experimentations). Milk samples were collected from 14 Kouri dairy cows in dry season (March to June) and fatty acids (FA) were determined by gas chromatography. Overall, 32 FA have been identified. Kouri showed lower values (P < 0.001) in the sum of saturated FA (SFA, -10.9 pts), cis-9, cis-12 18:2 (-1.00 pt) (P < 0.01, higher values (P < 0.001) in the sum of monounsaturated FA (MUFA, +15.3 pts), C18:0) (+3.5 pts), cis-9, trans-11 C18:2-CLA (+1.00 pts), trans-11 18:1 (+1.4 pts) and (P < 0.01) in cis-9, C18:1 (+3.00 pts) acids. The differences between the milk FA profile of the Kouri cows and that obtained from meta-analytical data could be the possible consequence of the use of particular lake pastures by Kouri cows.

Development of phytase-expressing chlamydomonas reinhardtii for monogastric animal nutrition

Background

In plant-derived animal feedstuffs, nearly 80 % of the total phosphorus content is stored as phytate. However, phytate is poorly digested by monogastric animals such as poultry, swine and fish, as they lack the hydrolytic enzyme phytase; hence it is regarded as a nutritionally inactive compound from a phosphate bioavailability point of view. In addition, it also chelates important dietary minerals and essential amino acids. Therefore, dietary supplementation with bioavailable phosphate and exogenous phytases are required to achieve optimal animal growth. In order to simplify the obtaining and application processes, we developed a phytase expressing cell-wall deficient Chlamydomonas reinhardtii strain.

Results

In this work, we developed a transgenic microalgae expressing a fungal phytase to be used as a food supplement for monogastric animals. A codon optimized Aspergillus niger PhyA E228K phytase (mE228K) with improved performance at pH 3.5 was transformed into the plastid genome of Chlamydomonas reinhardtii in order to achieve optimal expression. We engineered a plastid-specific construction harboring the mE228K gene, which allowed us to obtain high expression level lines with measurable in vitro phytase activity. Both wild-type and cell-wall deficient strains were selected, as the latter is a suitable model for animal digestion. The enzymatic activity of the mE228K expressing lines were approximately 5 phytase units per gram of dry biomass at pH 3.5 and 37 °C, similar to physiological conditions and economically competitive for use in commercial activities.

Conclusions

A reference basis for the future biotechnological application of microalgae is provided in this work. A cell-wall deficient transgenic microalgae with phytase activity at gastrointestinal pH and temperature and suitable for pellet formation was developed. Moreover, the associated microalgae biomass costs of this strain would be between US$5 and US$60 per ton of feedstuff, similar to the US$2 per ton of feedstuffs of commercially available phytases. Our data provide evidence of phytate-hydrolyzing microalgae biomass for use as a food additive without the need for protein purification.

Engineering low phorbol ester Jatropha curcas seed by intercepting casbene biosynthesis

Casbene is a precursor to phorbol esters and down-regulating casbene synthase effectively reduces phorbol ester biosynthesis. Seed-specific reduction of phorbol ester (PE) helps develop Jatropha seed cake for animal nutrition. Phorbol esters (PEs) are diterpenoids present in some Euphorbiaceae family members like Jatropha curcas L. (Jatropha), a tropical shrub yielding high-quality oil suitable as feedstock for biodiesel and bio jet fuel. Jatropha seed contains up to 40 % of oil and can produce oil together with cake containing high-quality proteins. However, skin-irritating and cancer-promoting PEs make Jatropha cake meal unsuitable for animal nutrition and also raise some safety and environmental concerns on its planting and processing. Two casbene synthase gene (JcCASA163 and JcCASD168) homologues were cloned from Jatropha genome and both genes were highly expressed during seed development. In vitro functional analysis proved casbene synthase activity of JcCASA163 in converting geranylgeranyl diphosphate into casbene which has been speculated to be the precursor to PEs. A seed-specific promoter driving inverted repeats for RNAi interference targeting at either JcCASA163 or both genes could effectively down-regulate casbene synthase gene expression with concurrent marked reduction of PE level (by as much as 85 %) in seeds with no pleiotropic effects observed. Such engineered low PE in seed was heritable and co-segregated with the transgene. Our work implicated casbene synthase in Jatropha PE biosynthesis and provided evidence for casbene being the precursor for PEs. The success in reducing seed PE content through down-regulation of casbene synthase demonstrates the feasibility of intercepting PE biosynthesis in Jatropha seed to help address safety concerns on Jatropha plantation and seed processing and facilitate use of its seed protein for animal nutrition.