The aim of this study was to evaluate differences in efficiency of feed utilisation between buffalo calves with low and high residual feed intake (RFI) by comparing feed intake, nutrient digestibility, growth traits and blood metabolites. Eighteen male Murrah buffalo calves (aged 4-6 months; 70 ± 1.0 kg body weight) were fed ad libitum with a total mixed ration for 120 d. Based on linear regression models involving dry matter intake (DMI), average daily gain (ADG) and mid-test metabolic body size, calves were assigned into low and high RFI groups. The RFI varied from -0.33 to +0.28 kg DM/d with an average RFI of -0.14 and 0.14 kg DM/d in low and high RFI calves, respectively. Calves had a mean DMI of 1.9 and 2.4 kg/d and an ADG of 0.5 and 0.6 kg/d in low and high RFI groups, respectively. Low RFI calves ate 19.0% less DM each day and required significantly less metabolisable energy for maintenance compared with high RFI calves (12.5 vs. 16.7 MJ/d). Nutrient digestibility and nitrogen balance did not differ among low and high RFI calves. In more efficient animals (low RFI calves) higher (p < 0.05) plasma level of growth hormone, insulin-like growth factor-1 (IGF-1), triiodothyronine (T3) and lower concentration of thyroxin hormone were detected. No significant differences in levels of insulin, hydroxyproline, plasma and urine creatinine, total protein and albumin between high and low RFI groups were found. Blood metabolites showed significant (p < 0.05) differences at initial and final stages of study in both groups. At final stage of study, RFI showed negative correlations with growth hormone, IGF-1, T3, urine creatinine and albumin. Low RFI buffalo calves are more efficient in feed utilisation and the differences in blood metabolites are probably due to differences in feed intake and body metabolism.
To evaluate different levels of energy and protein for optimum growth of Murrah male buffalo calves, a growth trial (150 days) was conducted on 30 calves (body weight 202.5 ± 6.8 kg). Six diets were formulated to provide 90, 100 and 110% protein level and 90 and 110% energy level requirements for buffalo calves, derived from ICAR 2013 recommendations for buffaloes. The crude protein (CP) intake was increased with higher dietary CP, whereas no effect of energy levels or interaction between protein and energy was observed on CP intake. There were significant effects (P < 0.01) of the interaction between protein and energy (P < 0.05) on metabolizable energy (ME) intake. The digestibility of dry matter (DM), organic matter (OM) and non-fibrous carbohydrate (NFC) was higher (P < 0.0001) in high-energy groups compared to low-energy groups. The CP digestibility increased with the increased CP and ME of the rations. The absorbed N was improved linearly with an increased level of dietary CP, whereas the N retention was similar among all the groups distributed as per different energy or protein levels. The nutrient intake (protein or energy) per kg body weight (BW)(0.75) at various fortnight intervals was regressed linearly from the average daily gain (ADG) per kg BW(0.75). By setting the average daily gain at zero in the developed regression equation, a maintenance requirement was obtained, i.e. 133.1 kcal ME, 6.45 g CP and 3.95 g metabolizable protein (MP) per kg BW(0.75). Requirement for growth was 6.12 kcal ME, 0.46 g CP and 0.32 g MP per kg BW(0.75) per day. Metabolizable amino acid requirement was estimated from partitioning of MP intake and ADG. The ME requirements were lower, whereas the MP requirement of Murrah buffaloes was higher than ICAR (2013) recommendations.
Poultry production, health and wellbeing are highly dependent upon formulation of balanced rations in terms of energy, protein, and micronutrients (vitamins and minerals). Among all, minerals are required in fewer quantities, but they are very important to maintain the productivity in poultry. Minerals present in the feeds are less bioavailable and additional supplementation is obligatory to meet the physiological demands of poultry. Conventionally, minerals are supplemented as inorganic salts, which are less absorbed and, thus, a major proportion is excreted to the surroundings creating environment issues. Nano-minerals and organic mineral chelates are other alternative to be used as livestock and poultry feed supplements. Though organic minerals are more bioavailable than inorganic salts, their high cost limits its use. In contrast, nano-minerals are relatively easy to synthesize at a lower cost. Nano-minerals are of the size from 1–100 nm and due to such small size, there is an enormous increase in surface area and thus their biological responses. The biological response studies have signified better retention of nano-minerals as compared to inorganic salts, and consequently leached less to the environment preventing possible pollution. Apart from these, nano-minerals have been shown to enhance growth, egg production and quality, immune-modulation and antioxidant status, and at the same time economize the production by reducing the supplemental dose of minerals and improving the feed conversion ratio. Some nano-minerals and other nanoparticles have strong antimicrobial effects, which have been shown to reduce pathogenic microorganisms in the gut. Nano-minerals seem to be less toxic than conventional mineral sources. Though less, few studies have indicated toxic effects of nano-mineral supplementation at higher dose of application, which should be validated by more programmed studies. Nanotechnology in poultry production system is still in its budding stage and more detailed studies are warranted to validate, establish and search for new effects of nano-minerals as they sometimes produce effects beyond expectation. This review highlights the biological responses of nanominerals on poultry production performance, quality of meat and eggs, tissue retention, immunity, antioxidant activity and antimicrobial actions compared with their conventional mineral sources.
This study was conducted to evaluate the utilisation of the residual feed intake (RFI) as a feed efficiency selection tool and its relationship with methane emissions. Eighteen Murrah buffalo (Bubalus bubalis) heifers were fed ad libitum with total mixed ration (TMR) for 120 days. Based on linear regression models involving dry matter intake (DMI), average daily gain (ADG) and mid-test metabolic body size (MBW ), heifers were assigned into low and high RFI groups. The RFI varied from -0.09 to +0.12 kg DM/day with average RFI of -0.05 and 0.05 kg DM/day in low and high RFI heifers respectively. Low RFI heifers ate 11.6% less DM each day, yet average daily gain (ADG) and feed utilisation were comparable among low and high RFI groups. Low RFI heifers required significantly (p < .05) less metabolizable energy for maintenance (MEm) compared to high RFI heifers. Apparent nutrient digestibility showed non-significant difference (p > .05) among low and high RFI groups. Although the nitrogen balance was similar among heifers of low and high RFI groups, nitrogen metabolism was significantly higher (p > .05) in high RFI heifers. Comparison of data from heifers exhibiting the low (n = 9) and high (n = 9) RFI showed that the low RFI heifers have lower enteric methane production and methane losses than high RFI heifers. In conclusion, results of this study revealed that selection of more efficient buffalo heifers has multiple benefits, such as decreased feed intake and less emission of methane.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.