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We observed a sample of 20 representative Herbig Ae/Be stars and five A-typedebris discs with PACS onboard of Herschel. The observations were done inspectroscopic mode, and cover far-IR lines of [OI], [CII], CO, CH+, H2O and OH.We have a [OI]63 micron detection rate of 100% for the Herbig Ae/Be and 0% forthe debris discs. [OI]145 micron is only detected in 25%, CO J=18-17 in 45%(and less for higher J transitions) of the Herbig Ae/Be stars and for [CII] 157micron, we often found spatially variable background contamination. We show thefirst detection of water in a Herbig Ae disc, HD 163296, which has a settleddisc. Hydroxyl is detected as well in this disc. CH+, first seen in HD 100546,is now detected for the second time in a Herbig Ae star, HD 97048. We reportfluxes for each line and use the observations as line diagnostics of the gasproperties. Furthermore, we look for correlations between the strength of theemission lines and stellar or disc parameters, such as stellar luminosity, UVand X-ray flux, accretion rate, PAH band strength, and flaring. We find thatthe stellar UV flux is the dominant excitation mechanism of [OI]63 micron, withthe highest line fluxes found in those objects with a large amount of flaringand greatest PAH strength. Neither the amount of accretion nor the X-rayluminosity has an influence on the line strength. We find correlations betweenthe line flux of [OI]63 micron and [OI]145 micron, CO J = 18-17 and [OI]6300\AA, and between the continuum flux at 63 micron and at 1.3 mm, while we findweak correlations between the line flux of [OI]63 micron and the PAHluminosity, the line flux of CO J = 3-2, the continuum flux at 63 micron, thestellar effective temperature and the Brgamma luminosity. (Abbreviated version)

GASPS observations of Herbig Ae/Be stars with PACS/Herschel. The atomic and molecular content of their protoplanetary discs