https://hdl.handle.net/20.500.12852/30 Fri, 13 Nov 2026 23:40:25 GMT 2026-11-13T23:40:25Z https://hdl.handle.net/20.500.12852/4012 Antibacterial property of blue gum (Eucalyptus globulus ) essential oil against Staphylococcus aureus in Philippine native chicken Carisma, Rey S., Jr. <i>Staphylococcus aureus</i> is a gram-positive bacterium that can cause septicemia and affection of the skin, joints, as well as sepsis and death in poultry animals. It is the most common cause of bumblefoot in chickens. <i>Eucalyptus</i> is rich in substances such as 1,8 cineole, terpenes and phenolic compounds that are responsible for inhibiting bacterial growth. The study was conducted to assess the minimum inhibitory concentration and zone of inhibition as well as evaluation of the concentration of <i>eucalyptus</i> oil according to potency. This research involved a total of 30 Petri plates, 100µl <i>Staphylococcus aureus</i> bacteria, 500µl tylosin at higher dose, 250µl tylosin at lower dose, 500µl VCO, 500µl distilled water. The concentrations were laid out using a complete randomized design (CRD) and two-factor (CRD). The EEO assessed through MIC after 24 hours of post exposure revealed that 100% EEO concentration has the highest mean percentage (62.20%). In addition, treatments 85% to 100% EEO concentration had a wider ZOI. Furthermore, the results show that the antibacterial potency of Blue Gum (<i>Eucalyptus globulus</i>) against <i>Staphylococcus aureus</i> is 75.32%, which means that the antibacterial property of EEO is potent, based on standard potency of 60 to 150 percent. Thus, EEO can act as an alternative in controlling <i>Staphylococcus aureus</i> isolated from Philippine Native Chicken. Abstract only Mon, 01 Apr 2024 00:00:00 GMT https://hdl.handle.net/20.500.12852/4012 2024-04-01T00:00:00Z https://hdl.handle.net/20.500.12852/4011 Effects of various exogenous emulsifiers and fat sources on nutrient digestibility, growth performance and carcass characteristics of broiler chickens Alapar, Krishna Mae M. Fat sources serve as key energy sources. However, the digestibility of fats in young broilers is limited due to immature digestive systems. To address this, exogenous emulsifiers have been considered for improving lipid utilization. This study investigated the interactive effects of two fat sources (coconut oil and palm oil) and six diet types (PC, PC+Polyethylene Glycol Ricinoleate, NC, NC+Polyethylene Glycol Ricinoleate, NC+Lysophospholipid, and NC+Solergy), on nutrient digestibility, energy balance, growth performance, carcass traits, serum lipid profile, and economic efficiency of broiler chickens. PC diets were formulated with standard metabolizable energy (ME) levels, while NC diets had a 75 kcal/kg ME reduction. Study 1 involved a digestibility trial using 72 broilers in a 2×6 factorial completely randomized design (CRD), which showed that coconut oil significantly improved the apparent total tract digestibility (ATTD) of DM, CP, EE, Ash, GE, and energy values (AME and AMEn) compared to palm oil. While significant interaction was observed only for crude fiber digestibility. Emulsifier supplementation, regardless of type, did not significantly improve energy balance or digestibility. Study 2, which included 1,200 broilers in a 2×6 factorial randomized complete blocked design (RCBD), found a significant interaction between fat source and diet type on final body weight and overall feed conversion ratio (FCR). Also, adverse effects were not observed from using energy-deficient diets. Coconut oil also resulted in higher total cholesterol, HDL, and LDL levels, but still within normal physiological ranges. Economic analysis favored the coconut oil group, specifically CO-NC, over the palm oil group, reflecting a higher margin over feed cost alongside improved digestibility and production performance. In conclusion, coconut oil improved energy balance, nutrient digestibility, and economic returns. No consistent interaction between fat source and diet type was observed, and emulsifiers had no significant effect. Thus, crude coconut oil is a cost-effective fat source, even without emulsifiers in energy-reduced broiler diets. Abstract only Tue, 01 Jul 2025 00:00:00 GMT https://hdl.handle.net/20.500.12852/4011 2025-07-01T00:00:00Z https://hdl.handle.net/20.500.12852/3993 Evaluation of biogas production potential of shrimp (Penaeus monodon Fabricius, 1798) aquaculture sludge with cow dung inoculum Lucena, Dee B. Shrimp aquaculture generates substantial quantities of organic waste, particularly bottom sludge, which poses both environmental and management challenges. This study evaluated the biogas production potential of shrimp aquaculture sludge through anaerobic digestion, focusing on the effect of varying substrate-to-inoculum (S/I) ratios on methane yield, methane content, and the digestate’s solid reduction. Batch anaerobic digestion trials were conducted under mesophilic conditions for 30 days using cow dung as inoculum. Treatments included S/I ratios of 0.5:1, 1.0:1, 1.5:1, and 2.0:1 based on volatile solids (VS), along with an inoculum-only control (Blank). Results showed that the S/I = 1.5:1 S/I achieved the highest methane yield of 8.82 mL CH₄/g VS and reached a peak methane content of 78.76%. This indicates that increasing the organic loading rate enhances biogas and methane production up to an optimal point, beyond which further increase does not proportionally improve methane yield. Conversely, the lowest S/I ratio (0.5:1) achieved the greatest reduction in solids, with 90.12% TS and 94.03% VS reduction. Despite its lower methane output, this ratio resulted in effective substrate stabilization, which is favorable for waste treatment objectives. These findings suggest a trade-off between energy recovery and waste stabilization, emphasizing the importance of selecting appropriate S/I ratios based on intended outcomes. Overall, the results demonstrate that shrimp aquaculture sludge is a promising substrate for anaerobic digestion, offering dual benefits of renewable energy generation and organic waste treatment. Optimizing the S/I ratio is essential to balance methane production with effective waste stabilization. Abstract only Tue, 01 Jul 2025 00:00:00 GMT https://hdl.handle.net/20.500.12852/3993 2025-07-01T00:00:00Z https://hdl.handle.net/20.500.12852/3992 Agronomic and yield performance of two rice (Oryza sativa L.) Azucena bi-parental mutant population grow under conventional and field rapid generation advance conditions in Los Baños, Laguna, Philippines Gandas, Darren Joy G. Rice breeding is constrained by prolonged generation cycles, limiting the rapid development of improved cultivars. To accelerate breeding, the Field Rapid Generation Advance (FRGA) approach was employed. This study assessed and compared the agronomic traits, yield performance, and associated costs of Azucena bi-parental mutants under conventional and FRGA setups. In the F₂ generation, MON 329 × Azucena (P1) and Azucena × MON 329 (P2) headed at 81 days and matured at 104 days, with P1 producing taller plants, more tillers, and higher yield, while P2 had longer panicles. In the F₃ generation under conventional conditions, P1 headed earlier at 75.68 days, matured at 105.18 days, produced more tillers and longer panicles, and yielded 2,840.89 kg ha⁻¹. Under FRGA, plants matured 5–10 days earlier but showed reduced height, tiller number, panicle length, and yield, with P1 producing 977.08 kg ha⁻¹ and P2 587.09 kg ha⁻¹. Correlation analysis showed a strong relationship between heading and maturity and identified tiller number as the trait most associated with yield. Scatter plots indicated wider trait dispersion under FRGA, reflecting stronger environmental influence. Selected lines P1 (C-11784-3, C-11784-30) and P2 (C-11785-30, C-11785-6) showed stable expression for advancement. Although FRGA shortened the generation cycle, partial budget analysis indicated higher costs and lower yield, resulting in a net loss of ₱193,849.12. Thus, FRGA is not economically feasible under the evaluated conditions but provides technical advantages for rapid line assessment and functions as a breeding acceleration platform rather than a cropping system. Abstract only Mon, 01 Dec 2025 00:00:00 GMT https://hdl.handle.net/20.500.12852/3992 2025-12-01T00:00:00Z