Over the years, the use of management and feeding strategies to enhance pig productivity while minimizing the use of antibiotic growth promoters has grown. Antibiotic growth promoters have been widely used as feed additives to reduce diet-related stress and improve pig performance. However, increasing concern about the consequences of long-term and increased use of antibiotic growth promoters in animal production has led to a paradigm shift towards the use of natural organic alternatives such as plant essential oils and organic acids in pig nutrition to enhance growth. Antibiotic growth promoters endanger human health by allowing multidrug-resistant genes to be transferred horizontally from non-pathogenic to pathogenic bacteria, as well as directly between animals and humans. Scientific research shows that alternative growth promoters such as essential oils and organic acids appear to improve pigs’ ability to prevent pathogenic bacteria from colonizing the intestinal system, stabilizing the gut microflora and promoting eubiosis, as well as improving immunity and antioxidant stability. The purpose of this review was to provide an in-depth review of organic acids and essential oils as growth promoters in pig production, as well as their effects on productivity and meat quality. Organic acids and essential oils in pig diets are a safe way to improve pig performance and welfare while producing antibiotic-free pork.

Phytogenic feed additives (PFA) are a diverse group of plant-derived materials that have gained considerable interest and use over the last few years in the food and agriculture industry. This is due to the banning of the use of antibiotic growth promoters, as well as an abundance of natural compounds with several perceived beneficial properties. PFA boast a wide range of physiology influencing properties including growth enhancement, stimulating feed intake, appetite and endogenous secretions, antiviral, antimicrobial, antioxidant, and immunomodulatory activities. However, despite the demonstrated potential of PFA and their phytochemical constituents in vitro, several technical limitations restrict their use and commercialisation in monogastric diets. Strategies to improve the bioavailability of phytic acid in pig and poultry diets are described, including encapsulation, feed enzymes, fermentation, cocktails and blends of phytogenics, blending PFA with organic acids and feed enzyme inclusion. The objective of this review article is to complement the body of knowledge considering new scientific evidence. In addition, the review describes some scientific techniques developed to improve the bioaccessibility and bioavailability and facilitate the application of PFA in pig and poultry nutrition.

Myrothamnus flabellifolius (Welw.) is used in African traditional medicine for the treatment of depression and mental disorder, asthma, infectious diseases, respiratory, inflammation, epilepsy, heart, wound, backaches, diabetes, kidney ailments, hypertension, hemorrhoids, gingivitis, shingles, stroke, and skins conditions. The effectiveness of M. flabellifolius is due to the presence of several secondary metabolites that have demonstrated efficacy in other cell and animal models. These metabolites are key in cell regulation and function and have potential use in animal production due to antimicrobial and antioxidant properties, for an improvement in growth performance, feed quality and palatability, gut microbial environment, function, and animal health. The purpose of this review is to provide a detailed account on the potential use of M. flabellifolius in animal nutrition. Limitations towards the use of this plant in animal nutrition, including toxicity, economic, and financial issues are discussed. Finally, novel strategies and technologies, e.g., microencapsulation, microbial fermentation, and essential oil extraction, used to unlock and improve nutrient bioaccessibility and bioavailability are clearly discussed towards the potential use of M. flabellifolius as a phytogenic additive in animal diets.

Y_ijklmnop = Response variable (L*, a*, and b*, pH, CL, tenderness, IMF, moisture content, FFDM, individual and group fatty acids)

The growing pressure and irreversible process of reducing and eliminating the use of antibiotic growth promoters (AGP) has stirred research towards development of phytogenic feed additives (PFA) as future alternatives for profitability and sustainability of poultry enterprises. The experiment aimed to compare the effects phytogenic Moringa oleifera leaf powder (MO) vs antibiotic growth promoter on growth performance, carcass characteristics, lymphoid organ indices, intestinal lesions, bloody excreta, microbial population, mortality, and economic viability of broiler chicken. Day-old Cobb-500 (n = 1600) unsexed chicks were allotted 16 pens and randomly assigned to a control standard basal diet group containing antibiotic growth promoters zinc bacitracin (486 mg) and salinomycin (650 mg per kg of feed) (CON) or a basal diet + 1% MO (MO1) or a basal + 3.0% MO (MO3), or basal diet + 5% MO (MO5) in a completely randomised design. The experiment lasted for 35 days. Supplementation with MO in diets significantly decreased ADFI, ADG, and FCR (P < 0.05) during the starter, grower, and finisher phases. The highest ADFI and ADG (P < 0.05) for the whole phase (d 1–35) was recorded in the control group, whilst the lowest was observed for in MO5. Feed conversion rate was highest (P < 0.05) in birds on MO1 diets during starter, grower, as well as the overall period whilst the lowest was noted for MO5 group. There was no significant effect of MO on breast, thigh and heart proportions (P < 0.05). The mean proportions of drumstick, wing, feet, neck, small intestine, liver, and gizzard (P < 0.05) improved with MO supplementation. The highest (P < 0.05) abdominal fat was observed in the control group. The spleen, Bursa of Fabricius, liver and intestine indices were highest in birds on MO5 group and comparable among other groups. Results show a reduction in necrotic scores with an increase in dietary MO levels. The control group and birds receiving 5% MO in diets recorded the least bloody excreta scores among all treatment groups (P < 0.05). Incremental levels of MO led to reduced total aerobic bacteria, E. coli, C. perfringens and increase lactobacillus spp. counts in all intestinal segments. Overall total cost of feed per bird was highest in birds in 5% MO (39.97) followed by 3% MO (30.58) and 1% MO (20.90) and lowest in CON (20.42). The CON group obtained the highest gross and net revenue per bird, whereas birds fed 5% MO recorded losses per bird. The highest economic efficiency (1,14) was achieved in birds on CON diets, and lowest in MO5 group (− 0.11) birds. Moringa oleifera leaf meal can be offered at 1–3% as an alternative to antibiotics for better feed conversion ratios, reduced abdominal fat, improved immune indicators, gut microbiota populations and low mortality. The high cost of MO reduces the economic efficiency and thus cheaper sources are necessary for sustainable small-scale communal and commercial enterprises.