Adopting a “seed, feed and weed” approach to ensure broiler chicks have the correct gut microflora will promote early gut development, efficient use of feed, reduced disease risk and shorter finishing times.
Stephen Collett (pictured above) of the University of Georgia’s Poultry Diagnostic Research Centre told a recent MSD intestinal health seminar it was essential to ensure good gut health from the start.
|Meeting the cocci challenge|
In France birds reared for the Label Rouge scheme had been treated for coccidia challenge to good effect over a period of 15 years, explained Alain Riggi of MSD Animal Health. The cost of vaccination had not been passed on to the retailer, but absorbed by producers through improved feed use – an important fact when encouraging retailers to accept vaccine use.
Data from Label Rouge broiler suppliers showed that feed conversion efficiency improved from 3.07:1 in untreated birds to 3.01:1 for vaccinated (Paracox 5) birds, daily liveweight gain rose from 26.72g to 27.68g and mortality fell from 1.68% to 0.92% where three consecutive crops were treated, he explained.
There was no hard and fast rule over coccidia vaccine use, suggested Linnea Newman, global technical consultant on gut health with MSD. While some producers used vaccine on every crop, others went for three crops vaccinated followed by two using in-feed anticoccidials. “It’s whatever works best for a particular unit, as the coccidial challenge will be different for each site,” she explained.
“We know a 16-day-old embryo has gut microflora from its parent, so we need to manage parent stock to pass on healthy gut flora via the eggs,” he explained. “We also need to be mindful of hygiene in the hatchery, as unwanted microflora can be picked up from contamination on the shell.
“Unlike chicks in the wild, which continue to pick up beneficial micro-flora after hatching from exposure to adult faeces in the nest, we need to replicate this seeding of the beneficial gut flora for the farmed bird. This can be achieved by spraying newly-hatched chicks with an appropriate competitive exclusion or probiotic product,” he added.
The first few days of life were critical. A target of 100% crop fill on day one and 80% on day three would help ameliorate the effect of lower intakes on subsequent days.
“Between two and five days old, chicks enter a stall phase, when growth of villi on the surface of the intestine slows. The bird undergoes a psychological change to recognise hunger. In the first few days it pecks everything because it thinks it’s food. If crop fill drops below these targets, a day’s growth is already lost,” he warned.
Having seeded the gut with beneficial flora, the task was then to feed this micro-flora to help it break down feed higher up the intestinal tract. “We can feed the micro-flora using organic acids applied to drinking water. If we get this right, villi in a healthy intestine can be seen easily with the naked eye in regular parallel lines.”
The UK’s practice of strict disinfection and removal of all bedding material between batches of broilers would help keep harmful micro-flora from developing for up to three weeks, compared to one week in the USA, where bedding is recycled. “While you have the advantage, the harmful micro-flora still need to be weeded out,” said Dr Collett.
“We can do this in a number of ways, but a healthy gut will help competitively exclude unwanted micro-flora. Other methods include use of essential oils and use of type one (yeast-based) Fimbriae blockers that make colonisation by unwanted microflora more difficult.
“The sooner you can apply competitive exclusion the better,” he said.
Matching nutrition to a disease challenge
Meeting the growing bird’s nutritional demand accurately can help reduce the effect of a coccidia challenge while protecting growth rates and feed use efficiency.
In work conducted at Oklahoma State University, a 38-day-old, 2.3kg bird required 12,500kcal ME to achieve targeted carcass weight unchallenged, said research leader Bob Teeter. Where vaccination was used, nutritional profiles needed to be syncronised to underpin bird performance.
Research suggested an earlier coccidiosis challenge had a lower effect on bird performance and feed conversion than a later challenge.
The nutritional plane on which birds were managed also influenced the effects of a coccidia challenge. “At 28 days old, birds fed on a low plane of nutrition had lost 5.7% of [targeted] bodyweight compared to 3.3% for birds fed on a high plane of nutrition. At 42 days old those figures were 17.4% and 10.6%, respectively.
“Where birds are challenged earlier in their lives (less than 29 days old), there is a potential to save 211kcal,” he suggested. “This can allow producers to take advantage of reduced energy finisher rations that offer savings in feed costs.”