ISSUE FOCUS FEED & ADDITIVE MAGAZINE October 2024 59 seaweed blend to bind three important pathogens (Clostridium perfringens, Escherichia coli and Salmonella Enterica serovar Typhimurium) and form agglomerates, with binding efficiencies of 60%, 42% and 76%, respectively. The agglomeration capacity demonstrated in this work shows how supplementation of animal diets with blends of macroalgae can contribute to the inhibition of pathogenic colonisation in the digestive tract, supporting improved gut health and animal performance. REDUCING THE NEGATIVE IMPACTS OF NECROTIC ENTERITIS IN BROILERS In order to further develop this hypothesis, Ocean Harvest Technology engaged Southern Poultry Research Group to conduct a Necrotic Enteritis Challenge trial at their facility in Georgia, USA. In this study, a total of 400 Ross 308 broilers were fed one of 4 dietary treatments for the duration of the 28-day trial; • Negative Control (NC, standard commercial diet) • Challenge Control (CC, NC + Necrotic Enteritis challenge) • CC + OFP 2.5 kg/t (Challenge Control + 2.5 kg/t of OceanFeed Poultry seaweed blend) • CC + OFP 5.0 kg/t (Challenge Control + 5.0 kg/t of OceanFeed Poultry seaweed blend) The challenge model consisted of ~750 oocysts E. maxima on day 14 of the study, and Clostridium strain on Days 19 and 20 of the study, using 1.0 mL of a 1.0 x 108 CFU/mL combination by gavage, as previously published by Hofacre, et al. (1998). The trial was established as a completely randomised block design, with 10 birds per pen, and 10 pens per treatment. The diets were formulated according to NRC guidelines with feedstuffs commonly used in the U.S. Rations were fed ad libitum from date of chick arrival to the conclusion of the trial. Birds and feed were weighed on days 0, 14, 22, and 28 of the study to evaluate performance metrics. Date and removal weight was recorded on all birds culled or found dead, and a gross necropsy was performed on all dead or culled birds to determine the bird sex and probable cause of death. A very strong challenge resulted in high mortality in the Challenge Control Group, of 49%. Supplementation with 5 kg/t OFP significantly reduced mortality to 33%, whereas mortality in birds supplemented with 2.5 kg/t OFP was intermediate to these groups at 44%, and 0% mortality was observed in the Negative Control group. Feed intake, liveweight gain and feed conversion ratio for the entire 28-day trial period are shown in Figure 1. Liveweight gain in Feed Intake Day 0 - 28 (kg/cage) Weight Gain Day 0-28 (kg/live bird) Negative Control Challenge Control CC+OFP 2.5 kg/t CC+OFP 5 kg/t Feed Conversion Ratio Day 0-28 (g/g) a ab ab bc ab a c a 20 18 16 14 12 10 1.58 1.56 1.54 1.52 1.5 1.48 1.46 3.5 3 2.5 2. 1.5 1 b c b b Figure 1. Feed intake, weight gain and feed conversion ratio of broilers under a Necrotic Enteritis Challenge abcValues within the same row not sharing superscripts denote significance differences (P ≤ 0.05). CC+OFP.2.5 kg/t, CC with 2.5 kg/tonne OceanFeed Poultry; CC+OFP 5 kg/t, CC with 5 kg/tonne OceanFeed Poultry;
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