Pistachio shell powder may be included in diets for weanling pigs without compromising growth performance or blood characteristics

An experiment was conducted to test the hypothesis that pistachio shell powder can be used as a fiber source in diets for weanling pigs without any negative impacts on pig growth performance. A total of 160 newly weaned pigs (initial body weight = 5.23 ± 0.54 kg) were allotted to 4 dietary treatments using a randomized complete block design with initial body weight being the blocking factor. There were 10 replicate pens per treatment. The control diet contained mainly corn and soybean meal and three additional diets were formulated to contain 5.0, 7.5, or 10.0% pistachio shell powder at the expense of corn. Dietary nutrient and energy concentrations were maintained among diets. Average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F) were calculated for phase 1 (d 1 to 21), phase 2 (d 22 to 42), and for the overall experiment. Blood samples were collected at the end of each phase to analyze for blood characteristics. Fecal scores were also recorded during phase 1. Phase 1 results indicated that ADG, final body weight, and G:F tended to increase as pistachio shell powder increased in the diet (quadratic; P < 0.10), and ADFI increased as pistachio shell powder increased in the diet (quadratic; P < 0.05). In phase 2 and overall, ADG and G:F were not affected by treatment, but ADFI from day 1 to 42 tended to increase as the inclusion of pistachio shell powder increased in the diets (quadratic, P < 0.10). On day 21, total protein in blood increased (quadratic, P < 0.05) with increasing pistachio shell powder in diets. Albumin and gamma-glutamyl transferase also increased (linear, P < 0.05) and chloride (linear, P < 0.10) tended to increase whereas glutamate dehydrogenase and bicarbonate (linear, P < 0.10) tended to decrease as pistachio shell powder increased in diets. On day 42, red blood cell count was reduced by pistachio shell powder (quadratic, P < 0.05) whereas mean corpuscular hemoglobin tended to increase (linear, P < 0.10), blood urea nitrogen increased (quadratic, P < 0.05), chloride tended to increase (quadratic, P < 0.10), and cholesterol increased (linear, P < 0.05) with increasing dietary pistachio shell powder. In conclusion, with the exception of a tendency for increased ADFI, overall growth performance of weanling pigs was not affected by including up to 10% pistachio shell powder in diets for weanling pigs indicating that pistachio shell powder may be added to diets for weanling pigs.