Abstract Industrial egg residue (IER) possesses substantial concentrations of calcium and crude protein. The objective of this study was to measure the digestibility and performance of broilers when IER was added to the feed. Four treatments were tested, which caused increasing replacement of calcitic limestone by IER (0, 35, 70 and 100%) during a 42-day production cycle. First, total bird excreta were collected from broilers with and without IER, and we determined dry matter digestibility, apparent metabolizable energy (AME), calcium, and nitrogen retention. The IER presented 7.5% of crude protein, 31% of calcium, 209 kcal/kg of AME and the digestibility coefficients for dry matter, crude protein, and calcium were calculated at 83.95%, 86.20%, and 67%, respectively. After the digestibility test, the effects of IER on performance, carcass and meat yield were evaluated. No significant differences between the treatments were found in terms of performance (weight gain, feed conversion, consumption, and mortality), and no differences were found in terms of carcass or meat yield. A linear decrease in the percentage of abdominal fat was observed with increasing inclusion of IER in feed. These findings suggest that IER can totally replace limestone (calcium carbonate) in broiler diets.

Abstract Our objective was to determine whether inclusion of industrial egg residue (IER) in the diets of laying hens would replace calcitic limestone without interfering with productive efficiency, egg quality or digestibility. In a first study (Experiment I), we used 30% IER in the diets of laying hens and found that the apparent digestibility coefficients were 51.6%, 42.8%, 51.6% and 17.8% for dry matter, crude protein, calcium and phosphorus, respectively. In the second study (Experiment II), we compared a control diet containing calcitic limestone with four diets containing increasing levels of IER, in proportions of 25%, 50%, 75% and 100%. During the first cycle (day 1–28), there was no difference between treatments in terms of productive performance or egg quality. During the second production cycle (day 29–56), we observed less food consumption by birds that ingested the highest levels of IER (100% substitution) than in controls. During the third cycle (day 57–84), we found that the inclusion of IER negatively affected performance, particularly lower production numbers, lower egg mass and higher feed conversion. Finally, during the third cycle, chickens broke and ingested their eggs shortly after laying. We conclude that the use of industrial egg residue cannot replace limestone in the feed of commercial laying hens, because it reduces performance and affects egg quality.

Abstract Abstract: This study evaluated the effect of oregano essential oil added to the feed of commercial laying hens. This research was focused on the analysis of biochemical changes linked to hepatic function, and protein and lipid metabolism. It was used 240 laying hens (59 weeks-old) distributed in a completely randomized design of six treatments (five repetitions with eight birds each). The experiments were constituted by a control treatment (CT) with the inclusion of zinc bacitracin and five treatments of oregano essential oil (OEO: 0, 50, 100, 150, and 200 mg.kg-1), respectively. After 28 days of feeding, an increase on serum levels of total proteins and globulins was observed on groups T150 and T200, as well as an increase on albumin levels on group CT. After 84 days of feeding, a significant reduction on total proteins and albumin was observed on group T200, as well as an increase in serum triglycerides. OEO at 200 mg.kg-1 increased globulin levels on day 28, which may be considered an effect in the inflammatory response, which increases serum immunoglobulins and proteins.