Nutritional Value Assessment of Fermented Citrus Pulp and its Effect on Performance and Egg Quality in Laying Hens

Abstract

The net energy (NE) value of feed reflects its nutritional value in the precision feeding system. This study was conducted to test the metabolizable energy and net energy of fermented citrus pulp (FCP) on laying hens, and to investigate its use in laying hens. Experiment 1: A reference diet based on corn soybean meal and a test diet in which 10% gross energy were replaced with FCP were used to meet the nutritional needs of Hy Line Brown laying hens for the NE value evaluation. Experiment 2: a nitrogen free diet and FCP diet were used for standard ileal amino acid digestibility (SIAAD) determination. Experiment 3: A total of 1080 Hy-Line Brown hens (36 weeks old) were randomly assigned into 5 treatments with 6 replicates per group and 36 hens per replicate. Five isocaloric and isonitrogenic diets contained a control (corn-soybean diet) and four FCP diets with 2.5, 5.0, 7.5, and 10.0% FCP respectively. The trail lasted for five weeks. Results showed that The GE was 16.32 MJ/kg. NE content was 5.14 MJ/kg. AME was 8.76 MJ/kg. AMEn was 8.61 MJ/kg. NE: AME ratio was 58.75%. NE: AMEn ratio was 59.69%. AME: GE ratio was 53.67%. There was no significantly difference on FI, BW, DM availability, nitrogen intake, and nitrogen retained (P = 0.92, P = 0.37, P = 0.97, P = 0.66, P = 0.51). FCP diet significantly increased 14.64% CP availability (P = 0.02) There was no difference in energy balance containing THP, HI, RE, RE as protein, RE as fat, AMEi, and NEi (P > 0.05). SIAAD of FCP was ranged from 38% to 76%. FCP diet had a lower AME, AMEn, and AME: GE ratio than the reference diet (P < 0.01). For the whole period, adding FCP in hens’ diet could linearly decreased egg weight (P < 0.01) and increase FCR (P = 0.02), and 7.5% FCP significantly decreased egg weight (P < 0.01). At week 5, FCP linearly decreased Albumen height and Haugh unit (P < 0.01, P = 0.01), and 10% FCP had a lower Albumen height than the control group and 2.5% FCP group (P = 0.02). FCP quadratically increased yolk color (P < 0.01), and 10%FCP had a lower yolk color than 7.5% FCP (P = 0.02). FCP linearly increased yellowness value of eggshell (P = 0.04). In conclusion, 5% FCP had no effect on laying performance and egg quality.

Keywords: Fermented citrus pulp, Laying hens, Net energy, Production performance