Rational Use of Feed to Promote Animal Healthy Feeding

Nowadays, ensuring global food production depends on various factors like climate change, resource scarcity, and a continuously increasing population, which creates tremendous pressure on traditional agricultural practices. Therefore, there is an urgent need to reimagine how to overcome limited natural resources to sustain food production, minimize environmental impact, and support animal and human nutrition. A well-defined strategic direction can be applied, focusing on a more in-depth exploration of underutilized feed resources and the valorization of agri-food by-products. While not a novel approach, this strategy enhances animal nutrition while promoting a circular bioeconomy.

Feed formulation based on conventional ingredients such as soybean meals and corn, often associated with deforestation, excessive water utilization, and significant greenhouse gas emissions, can be partially/ manipulated by including local, available, and accessible agri-food by-products to obtain high-quality animal feed, also reducing agricultural waste and farm environmental footprint. Valorizing agri-food by-products is not merely a technical solution; it represents a fundamental change in utilizing natural resources in agriculture. This path—producing more or enough (re)using less—aligns with present agricultural practices. Feed valorization methods such as fermentation can enhance these materials’ digestibility and nutritional profile. To address the multifaceted challenges of global food production, adopting an integrated strategy that brings together technological innovation, supportive and adequate policies, and sustainable economic models is essential.

This Editorial provides an overview of recent studies exploring various feed interventions—including fermentation processes, probiotic supplementation, natural additives, agri-food by-products, and alternative protein sources—to enhance productivity and product quality in poultry and small ruminants and also provide nutritional solutions for thermal stress mitigation. In this Special Issue “Rational Use of Feed to Promote Animal Healthy Feeding”, 10 papers were published, of which 9 research papers and 1 review paper were published. This Special Issue highlighted key research studies that explored nutritional interventions in broilers, laying hens, dairy goats, and lambs, emphasizing improvements in production performances, animal product quality, and gut health. Therefore, integrating these strategies into a circular bioeconomy framework is essential for achieving sustainable animal farming and ensuring food security.

Predescu et al. [1] reviewed the numerous effects of fermented feed utilization in broilers’ feed, emphasizing the benefits of fermented feed in reducing the by-products antinutrients and enhancing nutrient availability, reducing pathogenic microorganisms, and promoting a healthier gut microbiome. Beneficial microorganisms, particularly lactic acid bacteria, enhance gut health and immune response. Performance parameters like feed conversion ratio (FCR), final body weight (FBW), and feed intake (FI) are positively influenced by fermented feeds.

Complementing this, Ren et al. [2] investigated the effects of xylooligosaccharide (XOS) on the growth performance and intestinal health of broiler chickens challenged by avian pathogenic Escherichia coli (APEC). An improvement in FBW and average daily gain (ADG) was observed in APEC-challenged broilers, while FCR was also improved during the initial days of the experiment. The negative effects registered in APEC-challenged broilers led to decreased FBW and ADG and increased FCR, indicating that growth retardation was primarily due to intestinal disruption rather than reduced appetite. The XOS supplementation increased the count and density of jejunal goblet cells (crucial for maintaining the intestinal barrier). The jejunal villus height (VH) and crypt depth (CD) were significantly improved in XOS-supplemented broilers, indicating better intestinal morphology. The cecal microbiota was positively influenced by increasing the counts of Lactobacillus and enhancing the production of short-chain fatty acids (SCFAs) like acetate, butyrate, and valerate. The inflammatory cytokine expression in the jejunum was diminished in XOS-supplemented groups, suggesting a reduction in intestinal inflammation due to the protective effects of XOS against APEC. Additionally, XOS supplementation blocked the increases in the expression of virulent genes associated with E. coli, further contributing to maintaining intestinal health in challenged broilers.

Dumitru et al. [3] assessed the probiotic potential of Bacillus licheniformis (BL) in broilers fed cowpea-based diets; BL significantly improved BWG overall during the growing and finisher rearing phases. Improved tibia iron (Fe) and phosphorus (P) mineralization were observed while also reducing the calcium-phosphorus (Ca:P) ratio. Microbial analysis revealed that BL inclusion decreased coliform counts in the CWP diet and reduced E. coli in the ileum. Additionally, it lowered Clostridium spp. and Enterococcus spp. in the cecum of broilers on soybean meal (SBM) diets. The presence of Staphylococcus spp. in broiler feces was also reduced in CWP groups.

Matache et al. [4] investigated natural pigment supplementation from marigold and paprika extracts in laying hens’ diets. Their findings revealed that these natural additives utilize enhanced yolk color and improved egg quality during storage, serving as an effective alternative to synthetic colorants. Cornescu et al. [5] evaluated the effects of white grape pomace supplementation (6%) in laying hens’ diets under normal, low, and high-temperature conditions. While the benefits were most visible under low thermal stress conditions, improvements in parameters such as egg weight, production, and yolk quality indicate that such by-products dietary inclusion can be effectively used to support poultry performances under varying environmental conditions.

Other authors, such as Antunovic et al. [6], tested grape seed cake (5% and 10%) in lactating dairy goats, concluding that a 10% inclusion rate significantly enhances milk antioxidative activity. This improvement is attributed to the high polyphenol content of the grape seed cake, which helps alleviate lactation-induced stress and improve milk quality. A significant reduction in somatic cell count (SCC) was observed in the milk from goats in the grape seed cake group (10%) compared to the control and grape seed cake group (5%) groups, suggesting beneficial effects on udder health. The activity of superoxide dismutase (SOD) and glutathione reductase (GR) was significantly higher in the milk from the grape seed cake group (10%), indicating an enhanced milk antioxidative status. Cismileanu et al. [7] experimented with the substitution of conventional protein sources (sunflower meal 11.5% DM basis) with dietary linseed or hempseed in the diets of late lactation Murciano-Granadina dairy goats. Including these oilseeds significantly improved the fatty acid profiles of both milk and cheese. Notably, the enhanced levels of omega-3, omega-6 polyunsaturated fatty acids, and conjugated linoleic acid (CLA) contributed to lower atherogenic and thrombogenic indices, thereby elevating the nutritional quality of dairy products. Salavardic et al. [8] investigated the effects of extruded flaxseed (9%) and pumpkin seed cake (16%) as alternative protein sources in diets for growing Alpine goat kids. Although these dietary modifications did not alter the average daily weight gain, significant results in hematological and biochemical parameters indicated potential benefits in immune modulation. Costa et al. [9] examined the impact of incorporating sunflower cake (150, 300, and 450 g/kg DM) of high-oleic sunflower cakes derived from high-oleic seeds on finishing lambs, evaluating performance, carcass characteristics, meat quality, and intramuscular fatty acid composition. While sunflower cake inclusion did not significantly influence weight gain, dry matter intake, or metabolizable energy intake, an increase in neutral detergent fiber (NDF) and ether extract (EE) intake was noticed. Including sunflower cakes reduced hot and cold carcass yields and intramuscular fat content; oleic acid, rumenic acid, and EPA fatty acids linearly increased with high-oleic sunflower cake. Including high-oleic sunflower cake reduced saturated fatty acids, except stearic acid. Filip et al. [10] investigated samples of golden apples, red apples, carrots, celery, beetroots, and red potato peel waste as animal feed, focusing on their nutrient content and bioactive compounds. Various analyses highlighted the value of waste in providing essential nutrients in animal diets. Several analyses were performed collectively (chemical composition, X-ray diffraction analysis, thermogravimetric and differential thermal analyses, antioxidant activity assessment: DPPH and ABTS, and total phenolic content analysis), providing a comprehensive understanding of the structural, thermal, chemical, and bioactive properties of fruit and vegetable waste, emphasizing their potential as alternative animal feed sources.

The papers published within this Special Issue presented evidence of the benefits of different feed interventions in animal farm nutrition. From fermented feeds that mitigate antinutritional factors to the use of agri-food by-products and natural additives that enhance product quality, these studies highlight diverse strategies to promote farm animal health and sustainability, especially in poultry and small ruminants.