In Australia, 35 million tonnes of sugarcane are harvested annually which produces approx. 10 million tonnes of a by-product called bagasse. Sugarcane bagasse is an insoluble fibre source and recent studies in broilers indicated that bagasse can be added at 2% in both normal and reduced protein (RP) diets to improve FCR by 2-3 points and weight gain by 30-40 g (Sharma et al., 2021a,b). Thus, sugarcane bagasse may be a novel insoluble fibre source for poultry. Follow up studies were conducted to investigate the chemical composition of various insoluble fibre sources as well as the mode of action of bagasse as it stood out.

The arginine sparing benefits of guanidinoacetic acid (GAA) as the precursor of creatine in broilers fed reduced protein (RP) diets has been documented (Sharma et al., 2022). However, the effectiveness of GAA in RP diets on performance and gut health of broilers under heat stress is largely unknown. A 35-d experiment was conducted using four dietary treatments: a standard protein diet (SP, 221 and 207 g/kg CP in grower and finisher), a RP diet (201 and 187g/kg in grower and finisher), a RP diet with 0.92 g GAA per kg diet substituting 50% of supplemented arginine (GAA50) at one to one ratio and a RP diet with the same amount of GAA added on top (GAAtop). From d 0 to 10, all birds received the same diet as per Ross 308 requirements. Day-old male chicks were assigned to 64 pens (10 birds each) in two rooms. In each room, each diet was replicated 8 times. From d 25 to 35, birds in one room were subjected to a cyclic heat stress (32±1 ⸰ C for 8 hours). To assess intestinal permeability (InP), on d 27, an oral gavage of fluorescein isothiocyanate-dextran was used (4.16 mg/kg BW). There was no interaction between diets and heat stress for any of the performance parameters (Table 1). Body weight gain (BWG) was unaffected by dietary treatments. From d 10 to 24, feed intake and FCR were not affected. GAA50 followed by GAAtop significantly decreased the feed intake during the finisher phase (P<0.01) and from d 10 to 35 (P<0.001), compared with SP diet. At the same time, birds fed SP diet had the highest feed consumption. Heat stress reduced (P<0.0001) feed intake and BWG at any stage of the study but did not impact FCR. The GAA50 tended to reduce FCR from d 24 to 35 (P=0.086) and d 10 to 35 (P=0.082) compared with SP and RP. Heat stress increased (P<0.05) InP whereas diets had no effect. The results indicate that replacing 50% of supplemented arginine with GAA tends to improve FCR by reducing the feed intake under both thermoneutral and heat stress conditions. Additional analysis is underway to investigate association between GAA and gut health considering the involvement of creatine in energy balance of enterocyte and indirect effects on gut integrity.

Guanidinoacetic acid (GAA) spares L-Arginine (Arg) when supplemented in the diets of broilers as less Arg would be required to synthesise creatine for which GAA is a precursor. In chickens, Lcitrulline (Cit) can also be converted to Arg by the successive actions of two enzymes, argininosuccinate synthetase and argininosuccinate lyase in the kidney and other extrahepatic tissues (Dao et al., 2021). Data are sparse for comparing the effectiveness of GAA and Cit individually or in combination for replacing dietary Arg in broiler chickens. Using a completely randomised design, a 42-day study was conducted with 9 dietary treatments for grower (d 10 to 24) and finisher (d 24 to 42) phases. The first three diets included a control diet (T1) supplemented with 0.24% Arg and two semi-deficient and deficient diets that had 0.12% (T2) and no added (T3) Arg, respectively. Treatments 4, 5 and 6 were constructed by replacing 0.06% of Arg with 0.06% GAA (T4), 0.06% Cit (T5) and a combination (T6) of GAA and Cit, equivalent to 0.12% Arg. Treatments 7, 8 and 9 were made by replacing 0.12% of Arg with 0.12% GAA (T7), 0.12% Cit (T8) and a combination (T9) of GAA and Cit equivalent to 0.24% Arg. Both GAA and Cit replaced Arg at one to one ratio without any uplift designated for their energy contributions in the formulation matrix. Grower and finisher diets contained crude protein levels of 19.6% and 18.2% and digestible Arg of 1.28% and 1.18%, respectively. For the first 10 d of age, all birds received a common starter diet. A total of 864 day-old male off-sex Ross 308 chicks were assigned to 72 pens each accommodating 12 birds. Each diet was replicated 8 times.

Water is an essential nutrient for poultry and any deviation in water intake indicates issues related to nutrition, health and/or rearing environment. Williams et al. (2013) found that daily water consumption per bird increased over the course of time (1991 – 140.3 mL, 2000-2001 – 160.5 mL and 2010-2011 – 190.5 mL) and water to feed intake ratio (WI:FI) followed a similar pattern (1.90, 1.98 and 2.02, respectively). Thus, fast growing modern genetic strains of birds consume more water. The impact of dietary changes in water intake and WI:FI should be monitored regularly. For this purpose, a real time water measurement system was developed at the University of New England (Sharma et al., 2021). The system consisted of a 1.4-litre reservoir with a microcontroller to monitor water consumption. This paper summarises the results of five experiments to demonstrate the normal water consumption behaviour of broilers and the effects of nutrition on WI:FI and its relationship with feed efficiency.